i just wondered if it was posible to mod arena and/or daggerfall

i cant remember seing any mods for em

There was no editor released for either game, however Daggerfall did have a couple mods for it, nothing major.

player made or from betheshda?

On the UESP you can find many mods and utilities for Daggerfall.

http://www.uesp.net/wiki/Daggerfall:Files

One I really recommend is http://www.uesp.net/wiki/Daggerfall:AndyFall. It adds many new elements to the game such as knights on horse, more armor, new icons, new clothing and many other things. A must-have!

Another mod that is very cool is Daedrafall. A mod that twists Daggerfall's storyline by making you a Dremora who kills the original Daggerfall protagonist in Privateer's Hold, the starting dungeon. You are a Dremora who has been cursed by Mehrunes' Dagon to walk the plane of Tamriel as a mortal. I haven't played far enough with this quest mod, so I don't know if the whole storyline has been changed. Still, a nice mod to try when you've seen the first main quests hundreds of time.

Arena doesn't have any mod that I know of. Only save game hacking utilities.

The only 'Bethesda' -ish mods for Daggerfall was the CompUSA patch, other than that its all player made.

Must. Have. Link.

Enjoy.

http://www.uesp.net/file.shtml?dagger/files/daedrafall.zip