Barry Gross sells a full kit for making kitless pens - taps, dies, parts. I know he will be at MATES in a few weeks, but not sure if he will be at MPG. Per Barry in a question I asked him a few weeks ago, he only sells single start taps/dies not triple. If you are going to jump into triple starts, you might want to check out the Group Buy being proposed here on IAP to make that purchase.
Some of the other tooling you will need is sold by a few vendors that go to MPG - you will need mandrels, a sliding tap and die holder, a bunch of different drills, and a few other minor parts. Rick Harrel sells most of that tooling here on IAP - and his stuff is exceptionally high quality.
Bob Blanford (RGB Woodturner) and Chad Schimmel of Turners Warehouse (TurnersTV) both have good videos on needed tooling and making custom pens on YouTube. I am sure there are others, but I learned a lot from these two. Bob will be at MATES.