Hi,
How about you try this in 870
721 Pokemon where you have all:
1. 20 vivillon sprites --(same concept with unown)
2. rotom form sprites (6 forms)*
3. shellos and evolve (2 colors)*
4. jellicent and pre evole(2 colors)*
5. burmy and evolve (3 colors)*
6. basculin (2 colors) --(same concept with unown)
7. girantina 2 forms*
8. shaymin 2 forms*
9. arceus 18 forms*
10. darmatan (2 modes)* optional
11. deerling and evolve (4 forms)
12. Tornadus, Thundurus, and Landorus (2 form each)
13. kyurem (3 forms)*
14. keldeo 2 forms*
15. meloetta (2 forms)*
16. genesect 5 forms *
17. Flabébé, Floette, and Florges (5 colors) + AZ's unique Floette
18. Furfrou (10 haircuts)*optional
19. Aegislash (atk and def form)*
20. Pumpkaboo and Gourgeist (4 sizes)*optional
21. xerneas (2 forms)*
22. Hoopa (2 forms)*
23. primal forms of kyogre and groudon*
24. 48 mega evolution*
25. deoxys 4 forms*
*could be added on pokedex #722 onwards
if you get all of thes including optional, you will have
721 original pokedex + 76 forms + 48 megaevolution = 845 pokedex
25 pokedex for your own fakemons. Hope to enlighten you