The Imperial Guards were introduced in 1992 to replace the Imperial Soldiers (Blue Coats). Some reports state that the Imperial Guards are the same as the Imperial Soldiers but I like to think of them as British Royal Navy or Marines (Red Coats). They were eventually succeeded by the Imperial Armada in 1996 who we can view as Spanish conquistadors. The Imperial Guards did make a comeback in the 2009 re-release of the Lego Pirates theme.
Uniform wise the Imperial Guards differed to the Imperial Soldiers by the colours of their uniforms being red vs the Imperial Soldiers blue. Also the epaulets changed from red of the Imperial Soldiers to Blue.
The flag also saw a change to three red stripes on a white background with crossed cannons in the centre and a crown atop.
The Eldorado fortress was replaced with the Imperial Trading Post as the main base for the good forces. In the 2009 release the Imperials finally received a ship worthy of their forces in the Imperial Flagship, the largest Lego ship ever released. In contrast to history the imperials were mostly under shipped to their larger pirate foes.
1795 Imperial Cannon
The Imperial Cannon was a 36 piece Pirates set with 1 minifig released in 1994. It includes an Imperial cannon fort with a pier and an Imperial Guard Officer minifigure.
1872 Imperial Guard Camp
A small little set released in 1994, which comes with an Imperial Guard and Officer. This set is also called Soldier’s Forge.
6247 Bounty Boat (Admirals Launch)
Released in 1992, Bounty Boat was a 36 piece Pirates set with 3 minifigs. It includes a row boat, treasure chest and two Imperial Guards, one being an officer and one pirate prisoner Gonzo Goldbar minifig.
6263 Imperial Outpost
Released in 1995 and featuring 215 pieces and 3 Minfigs. Also comes with a cannon and rowboat.
6266 Cannon Cove (The Black Reef Bastion)
Cannon Cove was a 106 piece Pirates set with 3 minifigs released in 1993. It includes a fort with a block house and a canon and two Imperial Guards soldiers, a row boat with a Gonzo Goldbar minifigure.
6271 Imperial Flagship (HMS Sea Lion)
Released in 1992, the Imperial Flagship was a 317 piece Pirates set with 4 minifigs. It was re-released later in its life and came with a storage case.
6277 Imperial Trading Post (Port Royal)
Imperial Trading Post was a 608 piece Pirates set with 9 minifigs released in 1992. It includes a trading post with several cannons, merchant ship, dock and three buildings, a row boat and a ship with two sails and two Imperial Guard Minifigures, one Imperial Officer and Admiral Woodhouse and a pirate and a Gonzo Goldbar pirate minifigure.
10210 Imperial Flagship
The biggest Lego ship ever made and true to life bigger than the other pirate ships. This is the white whale of most Pirate Collections.