I've seen this come up over and over in other communities and there isn't a good central discussion about hearing protection options here. So I figured I'd start one that talks about specific products and what is good and bad about them.
For the last 2 years I've been pretty particular about finding earplugs that aren't disposable foamies, that feel comfortable under the helmet, don't fatigue the ears after long periods, and transmit enough sound to still enjoy comms/music as well as horns and emergency vehicles. The following are my personal experiences (including Amazon US links where possible).
Earasers:
These are my current most used ear plugs. They're very small and sit inside the ear canal with nothing extending out into the the external parts of the ear except a tiny flexible pull tab. The fact they don't extend into the external ear means no discomfort for me while my ears are being pressed by the helmet They're also made of a sturdier material than most which is confidence inspiring for long term use. Most places I find them for sale also include a case. They filter a decent amount of noise but these are one of the louder ones on the list and don't offer any interchangeable filters. Still they offer me enough protection to remove most loud road noises and all day riding is comfortable. Higher dB protection versions are available directly from the company.
EarPeace:
These are my newest acquisition and my second pick and I think they offer a great combo of comfort and adjustable noise protection. These are very soft silicone dual flange type ear plugs with a tiny pull tab molded into the largest flange. These come with 3 different filters that can be swapped. I have only tried the medium and high protection filters but I found the high protection muffled a tad too much of each frequency for me so I stuck with medium. Also included is a third ear plug as a spare, which I think is wonderful since these small things can be dropped or lost easily. Plus the included case has a trick hidden slot to store that extra plug just in case. I think the small size and soft material makes them easy to wear all day and the flanged style makes them fit a variety of ear sizes. What puts them in second place for me is that they offer so many "extras" for the price. Other versions labeled Motorsports or Safety are also offered, but the only differences are the color of the ear plug or case, the filters are the same.
Alpine Motosafe Pro:
Like the ones above, these offer a great mix of comfort and variable noise protection. These are also soft silicone double flange style ear plugs. The filters on these stick out of the back of the plug and serve dual purpose as a pull tab. The earplug itself is very small and the filter is soft sticking out the back so I don't feel it. The Pro set I've linked comes with two complete pairs of ear plugs, one with a medium filter and one with a high filter. They also come with a soft zippered case and an insertion tool. I find the soft case isn't as nice as the aluminum tube style cases others provide and the tool just seems silly. These can be bought in "non-Pro" sets that only have one set of earplugs and no case as well. These really are neck and neck with the EarPeace ear plugs for me and I've only rated those higher based on the case.
Eargasm:
Honestly these might have the best overall mix of good attenuation while still letting the right sounds through. They sound fairly natural just more quiet than no plugs at all. However these are the biggest in my ears (and I have pretty big ears) and they push on the tragus (the small thing covering the hole of the ear). These come with a second set of shorter tips, but they only change how deep in the canal they sit, not how large around they are. After about 10 minutes of riding I start to feel them, after about 30 they get annoying. So these are the least comfortable in the helmet and therefore least likely I'll wear. They also come with an aluminum case but it is quite a bit shorter and fatter than the others so it isn't pocketable. I can really only recommend if your helmet doesn't push on your ears at all or if you have very large ear canals. Otherwise these are great non-moto ear plugs.
Radians Custom Molded:
This is a little DIY kit that you use to mold your own custom shaped ear plugs. They come with two little tubs of putty that you split in half then mix together and form in each of your ears. It made for a fun little DIY project one evening while watching YouTube. I found them easy to mold with no major complications. Once set they are a firm silicone rubber with only a tiny amount of give/flex. Because of how these work, they are physically the largest in your ear and sit in a large part of your outer ear but they only became uncomfortable on very long rides of more than an hour without stops. The only provided case is a little plastic tub which is unwieldy for pocket use. Even though these cover the largest amount of the ear they seem to transmit the most sound of what I've tested, only barely an improvement on no plugs at all. I've discontinued use of these for motorcycle use and use them for other tasks like yard work. These are probably the best bet for people that are sensitive to having things inserted in their ear canals.
For the last 2 years I've been pretty particular about finding earplugs that aren't disposable foamies, that feel comfortable under the helmet, don't fatigue the ears after long periods, and transmit enough sound to still enjoy comms/music as well as horns and emergency vehicles. The following are my personal experiences (including Amazon US links where possible).
Earasers:
These are my current most used ear plugs. They're very small and sit inside the ear canal with nothing extending out into the the external parts of the ear except a tiny flexible pull tab. The fact they don't extend into the external ear means no discomfort for me while my ears are being pressed by the helmet They're also made of a sturdier material than most which is confidence inspiring for long term use. Most places I find them for sale also include a case. They filter a decent amount of noise but these are one of the louder ones on the list and don't offer any interchangeable filters. Still they offer me enough protection to remove most loud road noises and all day riding is comfortable. Higher dB protection versions are available directly from the company.
EarPeace:
These are my newest acquisition and my second pick and I think they offer a great combo of comfort and adjustable noise protection. These are very soft silicone dual flange type ear plugs with a tiny pull tab molded into the largest flange. These come with 3 different filters that can be swapped. I have only tried the medium and high protection filters but I found the high protection muffled a tad too much of each frequency for me so I stuck with medium. Also included is a third ear plug as a spare, which I think is wonderful since these small things can be dropped or lost easily. Plus the included case has a trick hidden slot to store that extra plug just in case. I think the small size and soft material makes them easy to wear all day and the flanged style makes them fit a variety of ear sizes. What puts them in second place for me is that they offer so many "extras" for the price. Other versions labeled Motorsports or Safety are also offered, but the only differences are the color of the ear plug or case, the filters are the same.
Alpine Motosafe Pro:
Like the ones above, these offer a great mix of comfort and variable noise protection. These are also soft silicone double flange style ear plugs. The filters on these stick out of the back of the plug and serve dual purpose as a pull tab. The earplug itself is very small and the filter is soft sticking out the back so I don't feel it. The Pro set I've linked comes with two complete pairs of ear plugs, one with a medium filter and one with a high filter. They also come with a soft zippered case and an insertion tool. I find the soft case isn't as nice as the aluminum tube style cases others provide and the tool just seems silly. These can be bought in "non-Pro" sets that only have one set of earplugs and no case as well. These really are neck and neck with the EarPeace ear plugs for me and I've only rated those higher based on the case.
Eargasm:
Honestly these might have the best overall mix of good attenuation while still letting the right sounds through. They sound fairly natural just more quiet than no plugs at all. However these are the biggest in my ears (and I have pretty big ears) and they push on the tragus (the small thing covering the hole of the ear). These come with a second set of shorter tips, but they only change how deep in the canal they sit, not how large around they are. After about 10 minutes of riding I start to feel them, after about 30 they get annoying. So these are the least comfortable in the helmet and therefore least likely I'll wear. They also come with an aluminum case but it is quite a bit shorter and fatter than the others so it isn't pocketable. I can really only recommend if your helmet doesn't push on your ears at all or if you have very large ear canals. Otherwise these are great non-moto ear plugs.
Radians Custom Molded:
This is a little DIY kit that you use to mold your own custom shaped ear plugs. They come with two little tubs of putty that you split in half then mix together and form in each of your ears. It made for a fun little DIY project one evening while watching YouTube. I found them easy to mold with no major complications. Once set they are a firm silicone rubber with only a tiny amount of give/flex. Because of how these work, they are physically the largest in your ear and sit in a large part of your outer ear but they only became uncomfortable on very long rides of more than an hour without stops. The only provided case is a little plastic tub which is unwieldy for pocket use. Even though these cover the largest amount of the ear they seem to transmit the most sound of what I've tested, only barely an improvement on no plugs at all. I've discontinued use of these for motorcycle use and use them for other tasks like yard work. These are probably the best bet for people that are sensitive to having things inserted in their ear canals.