From early on TSR had a couple of magazines they were publishing; one was Dragon, and the other was Dungeon. In 1980 Dragon issue #38 released a set of tables for upping the stakes of critical hits and critical fails. The table I use was based off this table, and expanded on and modified a little. But now that 5e is out, it was time to update it. I have been using these updated tables in Roll20 for a while now, but I decided to place them neatly on this site, and it ties in well with the House Rules for Tir Avalon.
I have done three different versions of the tables for different methods of playing. I have done one for Roll20, using the API script to import and export them. This REQUIRES access to the API, so Pro level members I think. The second is for table smith. With the last one being printable for TT game play.
Below you will find the three different options to download each version.