Back in the day when marvel was properly finding its stride it had two main team up titles featuring Spider-Man as the lead of Marvel Team-Up and Thing as the lead of Two-In-One. Over at DC they had a similar title in the form of Brave and the Bold headlined by Batman. These books played a pivotal role in the ecosystem of marvel which took advantage of the sheer popularity of Thing and Spider-Man to show off their more niche characters or ones who only got to appear in team books, these books were pivotal for establishing these outlying characters to readers who would otherwise never pick up the books those characters appear in.
We run into a similar issue today in the form of new characters struggling to find their audience or to get off of the ground. Deadpool had a team up book a while back but it was particularly short so no dice there. But I feel like a proper team-up title would help a lot of characters to get off of the ground or to return from obscurity. It would just be overall very positive for the health of 616 marvel as a whole.
Any thoughts? Any ideas for headliners? Was always partial to Squirrel Girl for it personally