Well, if you want to try the grumps again, I'd say Devil's Third or Doki Doki are good ones to watch, or just try the animated clips or compilations. I wouldn't recommend the Zelda ones (save for the CD-i ones), as while they are among the most popular, Arin is very negative of the series, and it shows. The Breath of the Wild one started off good, when they were jumping in blind, but at around episode 10, Arin had gotten a personal copy and gotten so far ahead that the episodes were him just going through the motions, which killed much of the charm.
Otherwise, beyond them, I'd say the Team Four Star guys make some pretty good Let's Plays. For them, I'd suggest starting with their Xenoverse play through.