Plus a Backcountry Research "Tulbag"
I like the redundancy principle with the Mountain Pipe. It's a CO2 inflator, which is absolutely necessary for re-seating your tire bead if you're running tubeless, plus a (crappy) pump as a back up. The barrel is hollow so you can stash a few tube patches and a few tire patches in there.
The Awesome Strap will hold a tube, a 16g or 20g CO2 cartridge, plus a pair of tire levers securely under your seat. A few wraps of good old duct tape around that CO2 cartridge might come in handy as a tire boot or as an improvised repair for your shorts, or your shins or your bike. Craig has admonished me of the virtues of always having duct tape at your disposal on more than one occasion. The Tulbag (or other similar small container... like an old sock or whatever) has the rest of the junk you'll need to prevent a walk-out safely tucked away in a jersey pocket. Here's what I like to bring: -a shifter cable (you might add brake cable if you're running bb7s or similar) -cleat bolt (you might add an entire cleat if you're cautious) -a valve stem -a valve core -a schrader adapter -a quick-link for your chain -a tube of vulcanizer for your patches (helps if it's not dried out) -a chain pin -Park tire boots -a few more tube and tire patches -a multi-tool with an integrated chain breaker plus Torx head for rotor bolts -spare derailleur hanger -a zip-tie or 2 -an alcohol or antiseptic wipe packet or 2
Steve Smith once mentioned a bandana or cravat as an valuable addition and I've since included it. It comes in handy for cleaning sealant from the inside of a tire that you plan to patch or boot, suspends a busted arm/clavicle, mops sweat, makes for dire emergency TP, etc. A shortcoming of this pack-free setup is not being able to easily carry spare spokes and nipples. You're more limited on how much water you can carry as well. Obviously this doesn't cover your first aid, lighting, or seasonal clothing needs but it's a decent base kit for most of your close-to-home rides and it's been working fairly well for me so far. I usually forgot to check the contents of my hydration pack before rides anyway which left me hoofing it with a big bag full of empty patch wrappers, a quintuple-snakebit tube covered in old sealant boogers, dried patch cement, and a rock-hard fossil of a Clif bar.