Sex Rex is pretty much a huge go-to. I invested heavily in Rule #1, but I realized that didn't affect idle regen, only running stamina regen.
That said, I did find a pair of fugly green running shoes and I can easily jog over a km without stopping now. Not as useful since I have a motorcycle, but I did a night-run for an airdrop that went remarkably smooth. Did it in a just some shorts, a shirt, and some ski visors that gave some extra stamina, not really expecting to actually survive. Ran out, go the drop, rested for stamina, and jogged straight on back to base non stop.
Best shoes ever. Worst color ever. Can I get them in white?
For mining, I was disappointed with the augur. it's obvious it needs the mods to increase damage vs stone, dirt, and metal, but at a base level, it's such trash. I fear the chainsaw isn't much better, particularly as a weapon.