There were many ways to get more performance from the Apple II. After all, it was sold at 1 MHz till the end. It did many things well at this speed, but power users wanted more. Here is an unusual item, a Stelation 68008 card. This let you write and run 68000 software on the Apple II. The external 8 bit bus fit the Apple architecture and the internal 16 and 32 bit operations happened much faster than the equivalent on a 6502. I used it for a small project at IAI and may still have the software someplace.
MCT produced the SpeedDemon. This used static RAM mirroring and a faster 65C02 (3 MHz I think). It works great and the startup beep is much shorter and higher frequency. The Apple II is rather snappy with an accelerator. Consider that after clock and instruction times are taken into account, an 8 MHz 65C02 is about the same as a 30 to 35 MHz 8086 IBM PC.
Titan Technologies made this Titan Accelerator IIe. This is another that runs about three times faster.
The AE Transwarp has to be set up with DIP switches for the speed the slots are accessed. This one is about three times faster.
This Zip Chip is 8 MHz and makes and Apple II a surprisingly fun system. Not pictured is a Zip Chip 4000 and a 10 MHz Rocket Chip that has failed. If one wished to attempt this today, the Western Design Center still sells 65C02 and 65C816 chips at up to 14 MHz.
Not really a speed item except in communications, but here is a Super-Com AppleTalk card. Very interesting and perhaps common in school computer labs but practically unknown in the user community.
When developing Apple II hardware you absolutely have to have one of these slot extenders to lift your board above the case for trouble shooting.