It really depends on your situation in each classroom. But for the most part
you can use most media with special needs students. Some special things you
might invest in: adaptive brushes (the kind with the bulb handle), model
magic (it is very clean and easy to use!), adaptive scissors (the kind with either
double holes for hand over hand cutting or the kind that spring back with a
loop that goes around the hand). There are adaptive crayons (they have a bulb
handle), but you can also take little bits of crayon (use similar colors like
all oranges or all warm colors) and melt in the bottom of a muffin tin. This
will make a big round crayon disk that is more easily held than a regular
crayon. You can build with duplos (large legos) if there are fine motor issues.
Lacing on large canvas, threading large beads with plastic lace, etc.
Depending on the disability and your ability for clean up (acess to water,
etc) you might want to use water color paints vs tempera. Use large paper
because, again depending on the disability, the students may not only have poor
fine motor skills but poorly developed gross motor skills as well.
I hope this helps a bit, there are many on the list who specialize with the
special needs student.