Free Online Design Editor with templates for everything from facebook posts to calendars to PowerPoint background designs.  Just create an account and start editing. 

Similar to Canva, however more depth of designs and logos and very  t-shirts specific and most designs can be purchased for a very low price of about $15 a monthly cancel anytime subscription or  with a one time purchase under $40 which is really inexpensive for a custom logo design that you can edit to your hearts content. 

Can also be used for product mock ups if you would be an online seller and would be in need of that.

Need to convert a file into something you can read for example have an .ai file and don't have illustrator?  Drop it into here and convert it to .PDF.  Doesn't work for everything everytime, but it has saved my a$$ a few times.

The best drawing app I've ever used.  It's sorta like photoshop, however with an ipad and the Apple Pencil, it's as close to drawing as I've ever come, and at $10 it's a great deal.  

Need some modern high quality clipart that has a transparent background and google search is letting you down?  This website probably has you covered.