There are some extra rules and attacks that almost every Pokémon can learn under the UPN PASBL. The attacks that almost every Pokémon can use are:

Tackle
Body Slam
Skull Bash
Headbutt

All of these attacks can be used by all Pokémon, with the exception of just Gastly and Haunter, who are gaseous in nature, and so cannot use these physical attacks. All others may use these though. There are two other attacks that every single Pokémon can use, and those attacks are:

Agility
Growl

Every Pokémon should have the ability to speed up. Thus, Agility is allowed for every Pokémon. Every Pokémon can also make a Growling noise, so this is allowed as well.

If the Pokémon has teeth, they may be permitted to use Bite, without any special rules. If the Pokémon has arms, they may also use Pound, without any special rules. Finally, if they have a tail, then the Pokémon can use Tail Whip without any special rules.

If Pokémon do not have any of the above moves on their attack list, then they can still use the attacks listed above, but with special rules (apart from Bite, which is allowed without any changes).

Tackle, Body Slam, Skull Bash, Headbutt Special Rules

If the Pokémon does not normally learn the attack, it may still use it, but because it has not been taught the move properly, the user takes 1/4 of the damage dealt out to the target.

Agility Special Rules

If the Pokémon does not normally learn Agility, it may still use it, but because it has not been taught the move properly, the user does not speed up as much as if a proper Agility was being used, and there is a 10% chance that the user will slip up while using the move, causing some damage.