Pick the tablet modifiers you want, narrow the list by rarity, tablet type and uses remaining, and this page writes the search string for you. Copy it into the stash or vendor search box and every tablet that matches lights up.
The string is a row of quoted groups separated by spaces, and a tablet has to match every group. They always come in the same order: rarity, tablet type, minimum uses remaining, then your modifiers. Your custom text goes last, added exactly as you type it, without quotes. A filter left neutral adds nothing, so with nothing set the string is empty.
What is the difference between any and all modifiers?
With any, the selected modifiers share one group joined by |, so a tablet with at least one of them matches. With all, each modifier gets its own group and the tablet needs every one. All costs three characters per modifier (two quotes and a space) instead of one, so it fills the limit faster.
How do tablet type and uses remaining narrow the search?
Each tablet type adds a short piece of its name, such as eac for Breach; ticking several matches any of them, and ticking all seven is the same as ticking none. Min. uses remaining takes 1 to 10 and matches that many uses or more: at least 5 becomes ([5-9]|10) us.
What happens when I enter a value on a modifier?
The group then only matches rolls from your value up to the top of that modifier's range, read from the roll(min-max) text on the item. Round values down to nearest 10 floors both your value and the range maximum first: the pattern gets shorter but coarser, accepting rolls a few points below your value and missing rolls above the last full ten.
Why does the counter warn me near 250 characters?
The builder counts against 250 characters, the limit it assumes for the in-game search field. The counter warns when 30 or fewer are left and turns red once you go over. Nothing is cut off for you: drop a modifier or switch to any until the string fits.