I like the attempt to be breadboard compatible. This also makes it easier to solder one-off projects on matrix board, but you seem to be wasting a lot of breadboard area. PCB's are not very expensive these days, but the cost still scales with PCB size.
For my own experiments, I combine breadboards with Lego. I have a pretty big Lego base plate permanently glued to a piece of MDF, and I glue little strips of Lego to a lot of other things, such as:
- Breadboards
- Breadboards sawn in two, and made with wider spacing (especially for adapter boards).
- USB Hub
- Logic Analyzer
- Programmer
- SMPS modules.
- Volt meter modules.
- Big connectors.
- LCD display
I find this method to work quite cheap, good and universal. Almost any electronic part or small measurement equipment can be glued (with hot glue) to a strip of Lego. The Lego base plate also prevents relative movement between all the modules. You can ealily pick up the whole thing at the end of a day and then put it in some drawer, and then continue next week.
Also, Logic analyzers (the USD 7 variant is good enough for most projects) and programmers (ST-Link V2, also < USD 10) are cheap. I have a bunch of them, and I tend to keep them attached via an USB hub semi permanently to the different projects I am working on. (I also have two Kings LA2016 Logic Analyzers, but have not glued Lego strips to them yet) For the different USB gadgets, I have some self made USB cords which are just 10cm long. Just enough for in between the Hub and the gadget. I also have some USB hubs (which are relatively big) with Lego glued both to the top and bottom. So small projects can just be stuck to the top of the USB hub, or you stick an programmer and LA on the hub, and then put the whole thing on a bigger baseplate.
Another nice thing are all the SMPS modules from Aliexpress. Some have displays, some don't. Some can generate upto 20V from a 5V USB plug (available on the already present USB hub).
For the rest, I am not very interested into an eco system of electronic modules from a single manufacturer. In my projects I usually combine parts from all sorts of different sources.