Did a little research and I got some info for you:
Here's a driver's side window retainer/guide that goes on the hinge side of the door (closest to front) on ebay, which is #21572 on the parts diagram and part number
E9TZ 1021573A:
https://www.ebay.com/itm/1989-1992-FORD-RANGER-AND-BRONCO-II-LH-SIDE-FRONT-DOOR-GLASS-RUN-RETAINER-/121259301891
I wasn't able to find a listing for the retainer that goes on the latch side (closest to rear), but on the diagram it's #222A00 and the part number is
F2TZ 10222A01-A for the driver's side. You'll have to do your own digging for that one.
There's also a guide that goes directly in the middle, diagram #21546 and part number
E9TZ 1021546-A, that I couldn't find a sales listing for.
As for the regulator assembly, which is the gear driven arm that actually moves the window up and down, they're readily available, just make sure you pick one up for the power windows and not the manual. Many of them come with new window motors as well, but you don't have to get one of those if you're on a budget. It's easy to swap the old motor onto the new regulator. Here it is on the Dorman website (quality products) without the motor. You'll have to purchase it from someone else though, Dorman doesn't sell them directly. They're sold by just about any auto parts store on the web or in person.
https://www.dormanproducts.com/p-3864-740-528.aspx?year=1989&make=Ford&model=Bronco%20II&parttype=Window%20Regulator&origin=YMM
Diagram referenced:
*Note: This diagram is of a passenger, or right, side door. The Ford part numbers (not diagram #s) are slightly different (by one number) for some of the driver and passenger side window parts, so be cautious of saying "it's only one number off, it should fit."