It all stems back from the very first set, the Base Set, originally printed in English in 1999 - the big red lizard had the most hit points (HP) at 120, making it the toughest Pocket Monster to take down, the highest damaging attack (Fire Spin for a whopping 100 damage) making it the hardest hitting Pokmon without a drawback (were looking at you Chansey with your Double-Edge attack) and had the best resistance, it resisted fighting types by 30 damage, it also has an alluring and unique Pokmon Power which essentially meant any deck could run a Charizard, if you had one
The good news is that, unlike Fusion Summoning where you need very specific monsters to achieve the goal, as long as you meet the level requirement with your tributes you can use any monsters as a tribute in Ritual Summoning
#4 M Gengar EX Set: XY Promos Increase: +$26.80 Current Market Price: $287.87 M Gengar EX has also been climbing steadily all yearthough some of that interest may be due to the return of Mega Pokmon in Pokmon Legends Z-A, and the return of Mega Gengar to the TCG in Phantasmal Flames and the upcoming Special Set Ascended Heroes
Creature spells you cast of the chosen type cost less to cast
Mechanics are another direction you can take with a theme deck