Published weekly by the Marvel Comics division in Great Britain, these were magazine sized books, containing only a small part of a comic adventure each issue, as well as fan fiction-ish adventures, posters, pull out sections, Thunder Art (I stole the title without knowing it!), and other various features depending on the issue.  They also seem to all contain bits of a comic entitled Power Pack at the end of each issue.

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Issue #61: 

Issue #62: 

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Issue #63: 

Issue #64: 

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Issue #65: 

Issue #66: 

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Issue #67: 

Issue #68: Dr. Dometome

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Issue #69: Dr. Dometome (2)

Issue #70: Dr. Dometome (3)

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July 16th, 1988

Comic adventure "Dr. Dometome", an adaptation of the episode by the same name.  ThunderCats Mini Poster No. 47, showing a scene from The Doom-Gaze with Cheetara running to save Roberbelle from S-s-slithe and Jackalman.  ThunderCats Fact File No. 17: Berbils.  Short story "Twister!" by Steve Alan, a story about the adventures on Destiny Atoll, and a tornado that threatens to destroy the small island.

Issue #71: Dr. Dometome (4)
July 23rd, 1988

Comic adventure "Dr. Dometome", an adaptation of the episode by the same name.  Mini Poster No. 48, showing Lion-O on a unicorn charging toward Mumm-ra as King Arthur on his steed (a scene from Excalibur).  ThunderCats Fact File No. 18: Captain Shiner.  Short story "The Enemy Below!" by Steve Alan, an underwater adventure starring Bengali on Destiny Atoll.

Issue #72: Bad Playmates
July 30th, 1988

Vultureman and S-s-slithe send a pair of Thunderdecoys to pose as the Thunderkittens in the comic adventure "Bad Playmates".  ThunderCats Lion-O Mask.  ThunderCats Fact File No. 19: Vultureman.  Short story "The Final Battle" by Steve Alan, a story about the adventures of Pumyra, Bengali, Lynx-O, Berbil Bert, and Berbil Bob on Destiny Atoll.  It's worth it for Pumyra dumping the two Berbils on their butts in the sand.

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Issue #73: Firefight! (Bad Playmates 2)

Issue #74: Bad Playmates (3)
August 13th, 1988

The exciting continuation of the comic adventure "Bad Playmates".  ThunderCats Mumm-Ra Mask.  Fact File No. 21: Snowman.  Short story "Shapeshade!" by Steve Alan, a story about Mumm-ra, and what lurks in the depths of his cauldron.

Issue #75: Bad Playmates (4)
August 20th, 1988

The exciting conclusion of the comic adventure "Bad Playmates".  ThunderCats Cat's Lair Blue Prints.  Short story "The Sign of Six!" by Steve Alan, about Geddontide, the mythical day when the six brothers of Mumm-Ra will reunite to destroy Mumm-Ra's evil.