I'm building a custom 'Magic' deck for my tricks. I have a few mentalism tricks that I perform so i decided to make a deck that contain all the cards I need.

I'm at 42 cards now which means I still need 10 cards and I was wondering if people could help me here.
the cards in the deck now are:

Well just a few more you might consider.

DB Red/Red
Blank Face Red Back
Blank Face Blue Back
Double face or your choice
Joker Red Back
Joker Blue Back
Any Different Color Back (Green, Pink, Yellow etc)

Twist

Are you aware that 39 and 40 are the same?
one side Ace of hearts one side Ace clubs
one side Ace of diamonds one side Ace spades
you can do some common names on some of them

Oops, nope didn't notice. 39 or 40 should be a Green square.. small mistype.

About the suggestions, I forgot to add something. As you may have or may not have noticed, until now, all my custom cards can have one and the same backdesign. The reason for this is that I can do a deck switch and magicly change all the cards into normal cards. This means that de double faced cards can't be an option.
The Jokers however are great additions and are now added:
43. Black and white Joker
44. Colored Joker

You can use some of the cards from David Regal's Color Changing Deck. For example: red ace of spades