Row 1, Stamp 1 — variant of Bochmann MS 114. Translates as "Airmail carries letters, newspapers, parcels"

Row 1, Stamp 2 — Bochmann Bremerhaven 2, celebrating 100th years since the founding of Bremerhaven

There's no drawing of it in Bochmann, so here's an example.

Row 1, Stamp 3 — Bochmann Berlin S+222. Commemorating Hitler's birthday.

There's no drawing of it in Bochmann, so here's an example.

Row 2, Stamp 1 & Row 3, Stamp 1 — Bochmann Innsbruck S21. Commemorating the 7th Tyrol Shooting Contest

Row 2, Stamp 2 — one of the varieties of a Gent postal inspection office handstamp from the WWI occupation of Belgium

Row 3, Stamp 2 — Aussig 1, Sudetenland

Row 3, Stamp 3 — Stuttgart Bahnhof 2 (Railway Station 2)

The Marine-Schiffspost (Naval Ship Post) cancel is from the
SMS Bremen, a light cruiser sunk by mines in December 1915.