Here are some Warhammer 40k names fitting for a Mechanicus character, incorporating various styles and levels of formality:

Formal & Hierarchical:

• Magos Biologis Theron: Suggests a high-ranking Magos specializing in biology.
• Tech-Priest Dominus Volkov: A powerful Tech-Priest, possibly a leader.
• Cognita Superior Anya Petrova: A highly skilled and respected Cognita (data analyst).
• Archmagos Xylos: A powerful and ancient Magos, possibly a leader of a forge world.
• Fabricator-General Kael: A high-ranking officer overseeing production.

More Technical & Functional:

• Servitor Unit 734-Omega: A designation for a servitor, highlighting its function.
• Tech-Adept Silas: A skilled technician, possibly specializing in a particular area.
• Skitarii Ranger Vex: A scout unit within the Skitarii legions.
• Data-Smith Kaelen: A specialist in data analysis and manipulation.
• Enginseer Theron: An engineer specializing in the design and maintenance of machines.

Mysterious & Ominous:

• The Iron Oracle: A mysterious figure, possibly a powerful psyker within the Mechanicus.
• The Silent Cog: A secretive and enigmatic individual.
• The Rusting Saint: A corrupted or fallen Tech-Priest.
• The Omnissiah's Hand: A title suggesting a powerful agent of the Machine God.
• Voidborn: A mysterious individual with unknown origins.

Names with a more human feel, but still fitting the Mechanicus aesthetic:

• Lysander: A strong, classic name that could suit a determined Tech-Priest.
• Seraphina: A name suggesting grace and precision, fitting for a skilled technician.
• Marius: A name that evokes a sense of strength and authority.
• Anya: A shorter, more modern name that could suit a younger Tech-Priest.
• Cassian: A name that suggests intelligence and cunning.

Remember that you can combine elements from these examples to create even more unique names. For example, you could combine "Magos" with a more human-sounding surname like "Magos Biologis Anya Petrova" or create a more descriptive title like "The Iron Oracle of Mars." The possibilities are vast within the lore of the Adeptus Mechanicus.