...Sniper Guard Post.
...Knockback Guard post (think military command, not tackle drone, doesn't require vulnerability to tractors)
Broken Golem Fortifications (that artillery golem in AI territory might still be broken and immobile, but it doesn't mean it's gun has stopped working)
...Glutton Guard Post - fires tackle drones that 'return to sender' with your ships, acts like a maw.
...Plasma Wormhole Guardianpost - only does splash damage to units covered by shields, otherwise hits only a single target, immobile like a tachyon guardian, tough like a post, spawns rarely and only on wormholes - instead of tachyon guardians.
...Forcefield Trapper Guardian. Impermeable forcefield that covers the exits into and out of a system, similar to the human trick of trapping a wave by blocking the routes out. Make it function like a Zenith Chameleon, while you're at it, only powering up and visible when it has a valid target to fire upon, otherwise the unit and its FF is invisible.
...Spider Carrier Guardian - spawns engine damaging drones, likes to kite. Do these Mobile Space Docks do engine repair anymore?
...Disco Guardian: I have no idea what they'd do, I just felt compelled to throw them in.
...More AI Taunts. More Frequent AI taunts. In Stephen Hawking's 'voice'.
...Bouncer Guardpost: fires anti-starship 'arachnids' that attrtion five seconds after leaving their system of origin. Which they will do after swallowing one of your starships or low cap ships, of course. Preferably they'd drag them further into AI territory, but alternatively, they'd head straight for player territory (or neinzul rocketry corps spawning planet) and then die.