Without knowing what saw you have its hard to say. Just so many fence arrangements. There are some aftermarket fences out there but they are usually to fit cast iron tables and rely on being able to mount a front rail to the saw for the fence to run on. They would likely cost more than some cheap saws too. Depending on the saw you have I would google to find DIY fence inprovements for that saw.
I have been known to use a sash clamp as a fence on my cheap table saw when needed. I infilled it with a strip of mdf cut to size to make it beefier, and use a jig I made to ensure it is straight before clamping it in position.
I also made a U shaped (flat bottomed) piece to go over the clamp for when I need it higher.