a person who likes giving presents in cases where no return of the favor is required is an altruistic person.
Altruistic- showing unselfish concern for others.
the main characteristic of altruism is signs of unconditional love and not needing reciprocation for any affection or whatever kind gesture that was displayed by that person.
Also, in it's more spiritual context, altruism is similar to being Christ-like, which includes the well-known slogan "What would Jesus do?" (WWJD).
You call a person who likes animals animal advocate, animal lover, etc.
a person who likes word games
GEEK
a panhandler!!!!
Hypochondriac
Abusive
There is no special name for a person who likes squirrels.
Speaker
a very intelligent person.
Hermit
A snuggler
A recluse.