please keep in mind these are tools at my home shop:
trans spring compressors, one for drums, one for rear of case springs t-350 , t-700 series.
T-400 drum is held by ring gear from t-400, it will work for 30 spline t-700 drum too
You need something to hold the trans case as you build... basic, but works
Notice snap ring pliers, sockets (metric) on t-700 series trans (4l60, 4l60e) stuff, ATSG books = good for DYI folks
Arbor press, bushing driver set, end wrenches (metric)..
wider view... vice, metal work bench 1/4 inch thick plate
Not seen= air tools, air compressor or use ratchet, speed handle. Inch pound torque wrench is good too. Micrometer, depth mic is good for setup of the pump clearance
That will get you started. Remember mistakes can be expensive and the valve bodies need attention in various areas a DYI may not know about , understand or get it done