Subject/Object
They are arriving tomorrow.
they
To (whom/who) does this concern?
whom
Another person (is/are) leaving.
is
(whose/who's) car are we riding in?
Whose
Colt himself said that tempest is fun.
Intensive
Edward helped me.
me
(Whoever/Whomever) finishes their first donut gets my donut too.
Whoever
Most of the party guests (has/have) left.
have
who's
Luke is A good teacher himself.
Intensive
Jerry wants it.
it
who
Anybody can (has/have) a pizza slice.
have (idk honestly anybody is singular so has but have sounds grammatically correct)
This is Red Gummy Bear and (its/it's) a Blooket profile.
it's
Michael is teaching himself how to use 4 mallet technique for In the Sky.
Reflexive