Total Recommendations: 4
They both not just using cards and battling monsters, these animes are also similar by that there is an another world which belongs to the monsters which are battling in the real world.
They both are animes which based on video games and have monsters which related to children and also they both are rated to children.
Because you will identify and recognize some voice actors in Digimon Savers/Yu-Gi-Oh! Duel Monsters GX (Judai's voice actor plays Kouki during Manjoume's voice actor plays Agumon and I guess there are more...), they both have done on the same animation company (Toei Animation), the main character is called 'Aniki' by one of the best friends (Sho and Kenzan on Yu-Gi-Oh! Duel Monsters GX and Agumon on Digimon Savers) and... Battling monsters! XDDD
This series has the same form: A boy who wants to be a champion on some leagues, that meets his non human partner on the first episode, some guys who are supporting him, they both live only with their mother, a group of guys who wants to steel Pokemons/medals (such as Robrobo group/team Rocket) and the most important - the leagues.