2scm.com (site is still active, but no new content since 2010) was one of my favourites. It featured 18-22 year old lads doing solos and some duos with handjobs and oral, and an occasional fuck. Supposedly all of the guys were straight...yeah, right.

cobravideo.com had full-length films with twinks, mostly bareback. The site is now dead, as is its founder/producer who was murdered in 2007.

boybatter.com is also defunct...because its founders are in prison for murdering the Cobra Video founder.

seancody.com, founded in 2001, still exists...but the founder sold it to a huge conglomerate in 2015 and the models they cast suddenly got ten years older, and were no longer the "fratboy" type.

And speaking of frats, fratmen.com had a lot of handsome early-20's guys doing solos. A spinoff called fratpad.com had duos with sucking.

Those were all US sites. There were certainly lots of European sites that have disappeared. My favourite of those was sevp.com (Scandinavian Erotic Video Productions) which had lots of early-20's hunks fucking bareback, often outside. Many of the models kept a decent bush downstairs even after other studios began shaving their gents' upholstery.

GayTeenStudio.com had young Eurotwinks fucking like mad...but they were too young (some under 18) and the site got shut down. It rebranded as TheGayTeenStudio.com, but that's also dead.

There are no doubt many, many others, but this is a starter. I'll probably think of even more after I click "submit."