Please ID German Telegraph? Inspection? Stamps

I've just started building a World Classic collection and purchased a miscellany of stamp pages. On one for Grand Comoro a number of other stamps were added. They appear to be German, and some are telegraph or inspection stamps. I'm not seeing these in the Scott classic catalog. Can anyone identify them or tell me what they were for? Thanks! (This is my first post with a pic; hope it comes out ok.)

Hi.
Fourth row : telegraph stamps of Bavaria
Last row : very interesting stamps of private local post Strassburg (Strasbourg,now in France) with pictures of the cathedral

Nice showing of your stamps and welcome to the board ,you will find many helpful members here.

Hi SaborStamp,

The five round or elliptical labels are letter seals from various organisations.

The first three stamps in the fifth row are German telegraph stamps.

The others in the fifth and sixth rows are from other German town posts.

Thanks for the replies and for the help! I'm happy to know about the Strassburg stamps and I'll try to learn more about telegraph stamps in general.

Hi SaborStamp.

If you can show more detailed pictures we can probably identify the other German local post issues for you.

Fifth row : 4th & 5th are from Leipzig and 6th from Köln
Sixth row : first two and 5th are from Dresden ,and 6th from Berlin