In addition to Coloplast, Convatec & Hollister, I also contacted Marlen, Cymed & Dansac for samples. All were fairly generous with pouch samples & products. Fell in love with the Convatec Convex Moldable [well, as much as one can fall in love with an ostomy pouch ] so haven't tried any other ones in quite a while.
I also was able to get samples of Eakin and Adapt seals, just for asking. Hollister and Convatec also sent me their emergency kits which are very handy--canvas bags with scissors & mirrors. They will also send samples of stoma powder, paste, etc.
I still call for samples if there is a new product I want to try, like some recently mentioned the Brava elastic tape by Coloplast. They have actually run out of samples of it, but said I would receive it in a few weeks.