I like the ATtiny85. It is small, comes in a solder friendly DIP 8 case, has 8k Flash + 512 Bytes Ram, 5 to 6 IO pins at 8 MHz with no external parts.
But developement is a pain: no serial (ok, it is possible but needs ports) and debugWire is even more pain.
So how to approach this problem? Throw money at it. Use MicroView.
MicroView is a chip-sized Arduino compatible module with an on-board 64×48 pixel OLED display. It has to be programmed with a special USB adapter. With its small size it is optimal for using in small environments. And it has a breadboard friendly DIP form factor.
It is expensive. $40 per item. And a one time fee of $15 for the programmer. So nothing for eternal to build into each and every mini project.
Replace it by a ATtiny85 after debugging the code.
Yeah, it has a different footprint. A adapter is needed.
And here we go!
That is what this page is about: the MicroView to ATtiny85 adapter. It is a very simple small PCB with no parts on it beside some headers.
Project info at Lembke.eu page.