I own a wide assortment of bike tools but my all time favorite is the Topeak TT2524 Rachet Rocket Lite DX Tool. If you have never used a tiny ratchet in place of a set of allen keys, you might want to try this tool. I was a bit skeptical upon purchase as to how it would hold up to the forces needed to make adjustments, but no problem, it was powerful enough to release the front wheel through axel on my ST-2. No flat head screw driver, but does come with a Philips head driver and a couple of useful torx bits for dealing with disc brakes. The best part is its size (compactness). It can literally be carried in one's shirt or pants pocket. I simply put it in my trunk bag. there is a small open slot on the inside of the fabric case that I put some tire patches in, along with a cash bill or two. No more heavy allen wrench tools in my repair gear on the road. But, I do have to carry a chain tool. The main difference being that I use the tool kit all of the time and, hopefully, never the chain tool. the tool works like a charm on nearly every fitting on the Stromer's (or any other model bike)
https://smile.amazon.com/Topeak-TT2...=8-1&keywords=topeak+ratchet+rocket+lite+tool
https://smile.amazon.com/Topeak-TT2...=8-1&keywords=topeak+ratchet+rocket+lite+tool