These are Black Knight Squad Shiva and Gundam Bael, which I assembled in a streamlined process from my backlog of unbuilt model kits.
The reason for choosing them was that I was looking for mobile suits from different series that had a one-on-one battle image, and the color combination was interesting.
Personally, I was surprised by how good the Shiva's structure and finish were. Bael, whether due to individual variation or a structural issue, has very loose joints, making it difficult to photograph it standing on its own.

Building a model kit set - a one-on-one battle themed machine | アッキー's Gunpla works