The other nightmare package for this sort of thing is the humble D2Pak, every one of the damn things is different at least in the amount of metal on the bottom.
Ah yep, only thing you can hope for is to get most of it!
Related subject: PDSO-8 style packages. I don't think there's a JEDEC standard for these (or, there are many...). Naturally, this leads to a great diversity in packages you'll actually see. The biggest variation is in the metal sticking out the side of the 'tab' part: sometimes it's indicated on the drawing, often it's not dimensioned, and never is it indicated on the PCB layout (as a region for soldering pad area, or for keep-out to avoid shorts!).
And probably, manufacturers don't want to specify anything additional, as their packaging source may change as well...
SFPs, also things like SD card sockets (Another complete pain in the tail), and any circular connector that is PCB mount....
Ahh, speaking of -- there are a number of connectors where it's impossible to produce a "safe" footprint, per IPC-2221A or per the board fabricators' design rules. 1mm pitch THT headers are one case. The holes can't simultaneously be:
- Large enough i.d. to fit the pin tail (including pin and drill tolerances), and
- Enough annular ring to meet IPC/fab rules (usually 5 mils), and
- Enough clearance (pad to pad edge) to meet fab rules (usually 6 mils clearance).
THT headers aren't usually very dense (e.g., 2 rows), so routing them at least isn't horrible. I've seen circular connectors where the above three are already challenging enough, but there are pins inside a surrounding ring of pins, which are essentially impossible to route! Four layer boards, with custom pad stacks, are seemingly required for these beasts!
Tim