Red can go for Venusaur, Charizard, Blastoise, Lapras, and Snorlax.
Blue can go for Pidgeot, Arcanine, Alakazam, Machamp, Exeggutor, Gyarados, Aerodactyl, Tyranitar, and Rhyperior.
In a Super Multi Battle Legends battle, Red and Blue can choose two of any Pokemon from the lists above, stated by Bulbapedia.