A standard "X" (single or double) or "Z" stand would be fine. One way you can get an idea of suitable stands is to search for what places sell as a combo (stand + keyboard).

The "X" stand is the quickest to setup and easily folds up - so it allows for easily moving your keyboard around if it's not a "permanent" setup. Z Stands can be broken down - but they generally involve more breakdown steps. The benefit of a "Z" is it gives you less obstructed foot room. Generally the "X" stand doesn't get in the way even if there is less leg room. But a sitting configuration may favor the "Z".

Note that I see a review response where "Normans Musical Instruments" claims Yamaha's L3C does not fit the PSR F50. It's difficult to tell if this is correct or not - but the L3C does not have an explicit compatibility list that I could find. Therefore, I would tend to use more generic options that do not rely on keyboard grooves and screw locations (any X, Z stand).

If you want a branded stand, Yamaha makes the "PKBZ1 Z-Style Keyboard Stand" which is shown as: "Recommended for PSR, PSR-E, DJX, EZ Series keyboards".

That said, there are not significant differences in Z stands in terms of compatibility with the PSR.

I personally have X stands for all of my keyboards. Super heavy I have double-X. Most all of my keyboards use a single-X. I stand to play.

What keyboard stand is suitable for the Yamaha PSR F50?

You may want to check with your regional Yamaha distributor - this is not a synthesizer (thus not a supported product here on YamahaSynth.com), and it is not a model available in all markets worldwide. If this model is available where you live, they may have a recommendation on which stand to use.

Rather than well intentioned guesses, I recommend that you contact your regional Yamaha distributor (info in the back of your Owner’s Manual) or an authorized Yamaha PSR dealer (music store) in your area for their recommendation.

By the way: “This model (PSR F50) is not compatible with the attachable L3C keyboard stand.” — this from the information that Yamaha provides to authorized dealers.

A list of L3C compatible boards can easily be found on the corporate site:
“This stand was specifically fashioned to bolt directly to many of Yamaha's PSR-E, YPT, NP and NP-V Piaggero and EZ keyboards.”

Yamaha L3C Stand