I’d like to nominate two ideas:
The Clock Tower, by @Xaklor. This dungeon idea is undoubtedly one of the best ideas I’ve seen in a while. It introduces great new mechanics, introduces interesting and intriguing lore, and provides great boss battles. Additionally, the idea of Lore Scrolls is something I would love to see implemented through the entire game!
Dapper Ideas and Classy Classes by @Dappertron. I’ll split my comments into 2 parts:
Dapper Ideas: Dapper Ideas introduces many new, interesting weapons, some being as sweet and simple as a Doom Bow Staff, with others being as unique and interesting as split shots!
Classy Classes: Have you ever wanted to summon bird allies or latch onto enemies and deal massive damage to them? If so, you’d love Classy Classes! It introduces some of the most interesting class ideas I’ve heard of and includes 14 of them (if they were all added, the class number would be tripled!).