I have some suggestions, maybe you can add character from "next avengers: heroes of tomorrow" like james rogers (capt. america & black widow son), torunn (thor daughter), Henry Pym Jr. (ant man & wasp son), Azari (black panther & storm son), francis barton (hawkeye son) or maybe you can add more teen hero/villain like miss marvel (kamala khan), hope summers, ravager (rose wilson), terra, artemis, spider-gwen, spider-man (miles morales), silk (cindy moon), spider girl (anya corazon), spider girl (mayday parker), gwen pool, kate bishop, amadeus cho
and i have some suggestion about teams, you can add secret six (Catman, Deadshot, Cheshire, Rag Doll, Scandal Savage, and a Parademon), young justice (Aqualad, Robin/Nightwing, Kid Flash, Miss Martian, Superboy, Artemis, etc.), and Web Warriors (Spider-man, Agent Venom, kid arachnid, spider women, spider ham, spider-man noir, spider girl, scarlet spider, spider-man 2099)