If you are looking at model to paint try looking at the WHF line. they have a few goodies. Chaos hordes for character and some Icon stuff from tomb kings.
I find 1k sons to be very "unseen" powerful so there really is not a lot of converting. The troops are all the same (power armor and bolters all around please) but with charactful, Characters.
Army wise there is a TON of info one the CSM Tac/army list, Give that a brows.