Most sims recognize at least 3 devices.
For instance, I have a Fanatec CSWv2, Logitech G25 pedals on a bodnar USB cable, and Logitech G25 shifter on another bodnar USB cable for a total of 3 devices. These are all recognized by R3E, AMS, AC, pCARS, and rF2. Configuring "Frankenstein" systems such as this can sometimes be a challenge... I remember R3E being a pain because it kept expecting the pedals to be Fanatec as well, but in the end everything worked. rF2 will recognize some large number of devices, like 6(?).
Wreckfest, as I recall, only recognizes the pedals & wheel, but I haven't tried confirming that lately, so it may or may not support 3 devices. Most of the older sims recognize 3 devices with no difficulty (Race07, GTR2, & original rF).