How can I optimize my build for large (10+ players) parties?

I plan to soon join a 5e group with over 10 PCs in the party at any given time. Are there any feats, builds, classes, etc that can be used to capitalize on this very large party size?

This may seem like a very broad question, but I’m struggling to find anything at all that meets this criteria, so I can only assume that few answers exist. The obvious solution was to seek out anything that affects something like "all allies within 30 feet", but I’ve had difficulty finding any such thing. The first place that I checked was the Battle Master Fighter’s maneuvers, but all of those seem to only affect one ally at a time. Furthermore, due to Bardic Inspiration allowing only a single target, the Bard has very similar restrictions. Where else can I look?