Hi Sue, there is a magnific list of cacti and succulents on the tortoisetable page! but resuming it you can feed (in moderation ofcourse as they all have laxative effects if in excess), opuntias, aloes, hotentot figs, sedums, agaves, gasterias, christmas/easter cactus, etc..
Regarding the propagation the easiest way is just like sandy advised, you get some cuttings/pads and leave them for a week or two to dry or maybe even more now in the cold weather, until a dry calous form in the end of the pad.
Then you stick it 2/3 down or even halfway down on soil/top soil, even better if done in top soil mixed with gravel for better drainage and you do not water it for a least 1 month or until you see some new growth forming. and when roots established and new pads present you water them only once every 2 weeks on the summer and in the winter very very rarely, only if you see the soil is bone dry or if you see the pads starting to shrink a bit (sign of dehidration).
In the summer you can do the propagation outside if proper hot and not very rainy. in the cold months this first stage I do it indoors, either on my growhouses (greenhouses) or even under the lights of my tortoise tables.
I have a few more spectacular opuntias I acquired since my original post
gonna post some update photos soon. this is turning into it another addiction besides keeping them for tortoise food
regards everyone