I've bought cuttape sets of resistors and capacitors from aliexpress.
The whole e24 range for resistors. A decent mix of ceramic caps. For a few bucks.
I store them in envelopes, still in the tape.
A grab bag for SMDs is difficult because often values aren't printed.
Prototyping with SMDs has the challenge that you need a PCB.
The last grab-bag I got about 3 years ago had a handful of strips of SMD resistors. Outside what's printed on the resistor there's no markings on the package. When I purchase SMDs directly from DigiKey or similar, the bag it comes in has the label, but the actual roll or strip with the 5-10 copies of the component does not. Only the unit itself has markings - and we all know you'll find little to no markings on SMD diodes. So I don't know how getting cuttape stuff would be any different. I would expect the components be left-over strips from production and as such I expect to have to figure out the properties of what-ever I get - that's part of the "fun".
Needing a PCB is just fine. I'm trying to go from bread-board to "not huge thru-hole" PCB when I make it into something permanent. If I get the right size, I can put them on my perf-board and still hack something together without creating a full PCB.
Anyway - with thru-hole I can usually find a drawer with something that gets close to what I want/need - not so much with SMD.
Biggest issue for me is AliExpress. I haven't ventured to use them yet. I'm sure it's not a rational thing, but I really cannot get myself to trust it. I've had enough bad experiences with purchases shipped from Hong Kong or mainland China via Ebay to avoid that as a source when I can.
Thanks for your input though. I do have the resistors covered, and I got my hand of electrolytic or film based caps (they look electrolytic - like a very small round case - but it just looks way too small to be that). Everything else - that's a problem. And last weekend I could really have used a few SMD resistor arrays. So I'll keep my eyes open for "cuttape" and other offerings.