If you breed an egg with a pokemon that has the ability "Flame Body" you only need 50% of the steps it would normaly take, and if you have a Pokemon with "Suction Cups" you have an increased rate of encountering a pokemon while fishing. Now I know these two effects but are there some other abilities that have a hidden function? Does a List exist or are there only a few?
Off the top of my head:
These abilities activate when the Pokemon is in the first spot of the party:
Most if not all of the above abilities are still active even when the Pokemon is fainted.
These Abilities will activate regardless of their position in the party:
In generations past:
Source for the ones I missed originally: