Sentai Fortress Robots

Super sentai used to have those flying fortresses but they were later replaced by fortress robots which were present in some sentai.

The homebase of the Turborangers- the Turbo Builder has a robot mode itself. It can combine with the Super Turbo Robot thus the first "Ultrazord" which was used to defeat an enlarged Ragorn. Its first appearance was when it defeated Zimba when the Turbo Robot was defeated.

The Magmabase in Fiveman. It combined with the Super Five Robo to form the Max Magma. Also, it was the first to be able to move around and be destroyed in the final battle.

Though not the homebase of the Zyurangers, King Brachion is another fortress type robot. It combined with Zyutei Daizyujin to form...
Kyukyoku Daizyujin. This awesome combination was first used when Dai Satan was first summoned by Bandora on Earth via the Satan Tower.

Dairanger had the most unusual fortress robot called Daimugen because he was sentient and a human form. Again not the homebase but this one forms a giant flying fortress that crushes enemies by landing on them. It was first used against the combined form of the Four Deva Kings.

The King Pyramider of the Kingranger served as Ohrangers' fortress robot. What makes it unique it's because it's the first fortress robot to be controlled by the sixth ranger. It has a robot mode and goes...
The King Pyramider Battle formation which fires the deadly legend beam. It was first used to defeat Keris of the Bara Empire.

The Victrailer used by the Carrangers houses their mecha (a later addition) which is sent into battle. It is fully mobile and can "walk" through the wheels. However it doesn't form an "Ultrazord".

The Bakuryuu Brachiosaurus is the first one to be based on an animal.

The Dekabase Robo is the most awesome as it goes beyond where the other fortresses had as now it can fully walk. Now it's one big giant robot piloted by Doggie and the Dekarangers. It was first used in episode 16 to battle the Mecha Cruncher which was way too huge for the Dekaranger Robo. It was later invaded by Aburera in the finale.