I know of summon necros being able to do it but what other forms do i need to look out for?

hammerdins, they are the top tppker

Hammerdins can now tppk if they drop a potion at the exact time you enter the portal and hostile.
Similar to the d1 dupe method

stronk hammerman can slain meny people with portals

Here's a question for you.

Why in the fuck are you still playing diablo 2 in 2012?

tppk is very fun

Tppk was fun back when if you tppked someone in a private baal game you would be blacklisted from the channel, hated by everyone, feared by all.

feared by all....LOL

all tppk'ers @ euro realm atm are crap

so far counted bout 600 attempts @ my pala, still waiting to lose some life from em....

I was serious about the feared part, back in like 08 09 when tppk was at its golden days, there was no such thing as a public baal run.

i expect in older patches the pk's were just more skilled then than they are now