I have too much time on my hands, so I found a few I remember:

King Ryan part 2, the screen takes on a sepia tone for the flashback, then goes red.

King Gavin part 2, when Ryan takes the tower, the screen shakes with the lightning.

On A Rail, Michael's name burn changes right before the end.

Halo 4, Castle Map Pack, Gavin's name changes.

Fuel, there's a montage of JJ having all sharp items taken away before he sits down to edit the monster-length video.

Let's Build - New Years, there's a little insert of Jeremy reacting to the others talking shit about him.

Ryan (or anyone else, but it's often Ryan) losing footage can result in great sarcastic text inserts. They're common in Minecraft Let's Plays and Go!, but they're too numerous to list here. However, there's only one episode of Ryan's 2D Adventures, in Episode 99 - Golden Hoe.

They're a bit different, but there are also editing remixes in Roof Boat, Car Wash, Friendermen Don't Dance, and Let's Build Ice Cube Part 2. All Lindsay's work except Ice Cube, which was JJ. Many of the old Let's Builds that JJ edited have picture inserts illustrating what they're discussing, and some are pretty funny.

If you like snappy editing that adds to a video, check out some old Inside Gaming stuff. They add quick glimpses of photoshopped images and text which are often hilarious. The Q&A videos are some of my favourites.