About which nations/ethnies Turks have jokes about? Can you give one example?

Answer 1

Yes, the 1st and the main ethnic jokes are about famous Laz man Temel as "fidget" said above.

Also we have jokes about the people from Kayseri(a city in the middle Anatolia) which are so stingy. One of them:

Three friends, Tolga from Istanbul, Fırat(Kurdish) from Diyarbakır and Hüseyin from Kayseri died in a traffic accident. But after a day Tolga came back to the life again and his confused friends asked:

"Didn't you die? How did u come again?"

Tolga:
"Yes, me, Fırat and Hüseyin died, Azrael welcomed us. He asked 5,000 $ per each to turn back again and I paid"

Friends:
"So, where is Fırat and Hüseyin?"

Tolga:
"Fırat was shouting 'Where is the Turkish Government?' that he was thinking govn have to pay this money"

"And Hüseyin was bargaining with Azrael to pay 3,000 $ but Azrael was insisting for 4,000 $"

Answer 2

A lot of Turkish jokes are at the expense of Laz (Black Sea) people. The epitomy of which is a man called Temel. A typical Temel joke is thus:

Temel's son, whose name is Ali, failed a mathematics test. Temel went to the school and spoke to his teacher, thus:
- "We have a large family, and if our relatives hear of this failure, we will be put to shame! You'd better give my son another chance!
- "Alright! Come to Avni Aker stadium on 23th April 1994 at 8 pm"
replied the teacher. And on the above date the teacher went to stadium. But he was confused because it was crowded. All the places were taken. And the teacher said to Ali:
-"Tell me what is the answer if we add five and five"
Ali replied:
-"Ten sir!"
Immediately after this reply, a sound came from stadium;
-"Give him one more chance, give him one more chance".