Slowbeef and
Diabetus: American Let's Players. Their joint channel is
Retsupurae, where they riff on bad video LPs, as well as on longplays (commentaryless playthroughs made by someone else) of games, usually really bad ones, or at least ones most people wouldn't want to play personally, but would want to see for the entertaining/riffable stuff. Separately they also do LPs and streams with viewer calls.
Notable example - Dark Seed.
Moderate swearing.
Two Best Friends: Canadian Let's Players. Despite the name, there can be anywhere between 2 to 4 people involved. They do both first-impression compilations of gameplay (for Machinima) as well as full LPs. Mostly restricted to console games, usually Japanese stuff. Tend to be self-referential.
Notable example - Silent Hill Downpour.
Moderate swearing.
Bro Team: Canadian Let's Player. Actually usually one guy. Does compilation videos, parodying "bro" mentality, or just flying off into inanity. Also does streams of random games with multiple other people.
Notable example - Mass Effect 3.
Moderate-high swearing.