On my gravel bike I use a rapha bar bag that I got on offer sometime ago which does the job of stashing a mini pump, multitool, plug kit, emergency clip bar, a cafe lock and if necessary a goretex jacket.
I have a frame bag, an ortlieb small frame bag, that gets used in the winter on longer rides but I tend to keep the bar bag on most of the time these days. I also have a salsa bolt on top tube bag which is handy with the bar bag for a few more snacks for longer rides etc.
Basically it’s handy having a few options that can be mixed and matched depending on where and how long your ride is, what weather etc.
Have also got a salsa tool roll thing that bolts to cage mounts which is handy for a minimal tool kit plus a pump on a bracket if going bag less but I use that less these days as i tend to strap under the top tube on the extra mounts and it’s always covered in crap. Also have a fidlock canister that does the same and clicks between 2 bikes easily but tend to only use this for extra storage when the other bags might be packed with other stuff such as when bikepacking etc. the salsa bag is a neater thing other than the British weather.