An excellent card for your economy, assuming you have enough valid targets in your deck to use it every turn it is out -- which means you might never want 3 copies in your deck, unless you build the entire deck around this card. Also important reminder: the traits on your Alter-Ego do not matter for this, as you can only use it in Hero form.
Here is a list of how many cards in each heroes' core deck qualify for Team-Building Exercise (Listed from most to least), to assist with determining whether or not it is worthwhile to include (and how many you might want to include). (List last updated September 24, 2026)
13/15: Iceman
10/15: Falcon, Phoenix, Spider-Ham
9/15: Angel, Ant-Man, Hercules
7/15: Cable (with Technovirus Purge), Psylocke
6/15: Thor
3/15: Black Panther (Shuri), Maria Hill,
2/15: Black Panther (T'Challa), Domino, Nick Fury, Winter Soldier
1/15: Adam Warlock, Black Widow, Captain Marvel, Colossus, Cyclops, Daredevil, Deadpool, Doctor Strange, Drax, Echo, Gambit, Gamora, Hawkeye, Hulk, Hulkling, Ironheart, Jessica Jones, Jubilee, Luke Cage, Magik, Ms. Marvel, Nebula, Nova, Quicksilver, Rogue, Scarlet Witch, Shadowcat, She-Hulk, Spectrum, Spider-Woman, Tigra, Vision, War Machine, Wasp, Wolverine
0/15: Cable (without Technovirus Purge), Captain America, Ghost-Spider, Groot, Iron Man, Magneto, Nightcrawler, Rocket Raccoon, Silk, SP//dr, Spider-Man (Peter Parker), Spider-Man (Miles Morales), Star-Lord, Venom, Wonder Man, X-23
I will add later heroes as comments to this one, should an edit feature be unavailable at that time. If I missed anything, please feel free to correct me below.
EDIT 1: Forgot about reaction and response cards not benefitting, as well as 0 cost cards; adjusted card counts down to accurate numbers.