Alright great thanks! Any specific brand that you could recommend? Also, just making sure, but could I use flash for long exposure?
Alex, I'm not sure if you're asking about brands for the remote plunger... or brands for the flash.
I have (presumably somewhere around here) two different plungers. One was a braided metal cable ... fairly short (perhaps about 10") and a metal pin, metal threads, metal plunge button on the end. When you pushed in the button, there was a set-screw (knurled finger-screw) that you can snug down to hold the button in... if you wanted to take a very long exposure and just lock the button and walk away. It was mostly all metal. Of course I got these things back in the late 1970's... we didn't use so much plastic back then.
The "other" plunger is about 20 feet long... the shutter pin is also metal, but the 20' length isn't a cable -- it's an air-tube. There's an air-bulb at the end. Squeeze the bulb and air-pressure pushes the shutter pin. But this plunger would slowly leak air (you could not, for example, take a 5 minute exposure with it.)
I think it's been 35 years since I bought these and I probably didn't pay much attention to the brand. They both worked well and served their purpose.
Here's an example of one... note that this has the "screw lock" option and if you look at the alternatives... some of them have this screw lock and some do not. If you plan to use the release cable for "long" exposures, it's nice to be able to snug down the plunge lock and walk away.
Bower Cloth-Coated Cable Release With Lock (20") SR-716 B&H
As for long exposure flash...
When you use a flash, the flash fires once and typically it fires as soon as the shutter completely opens. You can hold the shutter open as long as you want but the flash doesn't fire again. Some flashes offer the option for "2nd curtain shutter sync" which means rather than fire the flash when the shutter OPENS... the flash is deferred until just before the shutter is about to CLOSE. But this requires a more advanced interface between camera and flash than an AE-1 would have.
There is also a notion of "multi-strobic" flash. You set the flash frequency (the rate at which it will fire... e.g. 4 times per second) and the total number of flashes (e.g. 8 flashes) and that would mean the flash is going to fire 8 times across a span of 2 seconds. This is use if, for example, you want to photograph an athlete performing some action and you want to capture their body at multiple points through the action (e.g. throwing a baseball for example). Of course you couldn't leave a shutter open for 2 full seconds in broad daylight so you'd probably move the athlete to a studio to take the shot -- but you get the idea.