What are the names of the metal photographed parts? The tombstones are inserted to clarify function.
I would like to order more of these metal parts, however, I do not know the terminology to Google for them. There are two different though similar parts:
Your terminology is correct: they're called tombstone (or bi-pin) fluorescent lampholders. In particular, those in the photo are locking or turn-type, a nice safety feature that makes it less likely for a lamp to fall out of the socket. A search at Amazon.com for Fluorescent Tombstone Lampholder found more than 30 similar devices.
N.B. There are two types, shorting and non-shorting, also called shunted and non-shunted. Be sure you examine your socket (you may need to pop off a plastic cover) and get the same type. Also, if you're converting from fluorescent to LED, check the type needed for the replacement tubes -- it might be different from your current lampholders.
I am only guessing here ... I'd describe them as tombstone bases if I were ordering over the phone. Maybe "tombstone brackets"? Sounds more official. Wouldn't it be cheaper and less trouble simply to buy a new complete fixture?
I have never seen just the ends being sold. I have seen "bare" fixtures ie no ballast for ~10$ at places like 1000bulbs.com I believe they came with t8/t12 style non shunted tombstones.
