Standard/regional:

litwick -> lampent -> chandelure: duskull -> dusclops -> dusknoir: honedge -> doublade -> aegislash -> aegislash_blade: galar_corsola (regional) -> cursola (regional): snorunt -> glalie -> froslass: fuecoco -> crocalor -> skeledirge: gastly -> haunter -> gengar:

Add picks:

Uncommon: hisui_zorua (regional) -> hisui_zoroark (regional): sandygast -> palossand: sinistea -> polteageist: greavard -> houndstone:

Rare: drifloon -> drifblim: yamask -> cofagrigus: galarian_yamask (regional) -> runerigus (regional): golett -> golurk: phantump -> trevenant:

Epic: cubone -> marowak -> alolan_marowak (regional): misdreavus -> mismagius: shuppet -> banette: pumpkaboo -> gourgeist:

Hatches: rowlet: dreepy:

Uniques:

sableye -> mega_sableye:

spiritomb:

rotom (regional):

basculin_white -> basculegion_male -> basculegion_female:

hoopa -> hoopa_unbound:

mimikyu -> mimikyu_busted:

mimikyu -> mimikyu_busted:

dhelmise:

flutter_mane:

gimmighoul -> gholdengo:

Legendaries:

giratina:

origin_giratina:

darkrai:

lunala:

marshadow:

blacephalon:

spectrier:

pecharunt: