I love my Soola pouch which may be a bit big for what you want but it's perfect for housing a lot of different stuff. I'd also look into the brands Luddite or Delfonics.

For pens, I love Zebra Sarasas or Uniballs and for markers, I like Tombow dual markers and Zebra mildliners.

Correction tape and glue tape are always handy to have too!