Running from 1952 to 1980, Fritz Leiber had a lots of appearances Fantastic magazine, including numerous Fafhrd and Mouser appearances.  The 1959 issue of Fantastic was notable as it was an ‘All Leiber Issue’ and featured numerous stories by Fritz.

Covers are only shown where they are for one of Fritz’s stories.

CoverStoryIssue
The Big Time (Part 1)1958 / 03
The Big Time (Part 2)1958 / 04
The Ship Sails at Midnight1950 / 09
The Enchanted Forest1950 / 10
I'm Looking for "Jeff"1952 / 09
Damnation Morning1959 / 08
http://www.lankhmar.co.uk/wp-content/uploads/2014/04/fantastic_195911.jpgLean Times in Lankhmar1959 / 11
The Reward1959 / 11
The Mind Spider1959 / 11
The Improper Authorities1959 / 11
The Haunted Future1959 / 11
When the Sea Kings Away1960 / 05
Mariana1960 / 02
Rats of Limbo1960 / 08
http://www.lankhmar.co.uk/wp-content/uploads/2014/04/fantastic_196011.jpgDeadly Moon1960 / 11
Scylla's Daughter1961 / 05
The Goggles of Dr. Dragonet1961 / 07
http://www.lankhmar.co.uk/wp-content/uploads/2014/04/fantastic_196111.jpgThe Hatchery of Dreams1961 / 11
http://www.lankhmar.co.uk/wp-content/uploads/2014/04/fantastic_196202.jpgA Bit of the Dark World1962 / 02
The Casket-Demon1963 / 03
Midnight in the Mirror World1964 / 10
When Brahma Wakes1968 / 01
The Cloud of Hate1963 / 05
http://www.lankhmar.co.uk/wp-content/uploads/2014/04/fantastic_196308.jpgBazaar of the Bizarre1963 / 08
http://www.lankhmar.co.uk/wp-content/uploads/2014/04/fantastic_196401.jpgLords of Quarmall Pt 11964 / 01
http://www.lankhmar.co.uk/wp-content/uploads/2014/04/fantastic_196402.jpgLords of Quarmall Pt 21964 / 02
Stardock1965 / 09
The Two Best Thieves in Lankhmar1968 / 08
Richmond, Late September1969 / 05
Trapped in the Shadowland1973 / 11
Under the Thumbs of the Gods1975 / 04