G is for “Gherkin” and “Great find!”
What else?
First G that comes to mind is Granularity:
- How detailed should your test case be?
- How many edge cases should you include?
- How extensive should your bug report be?
Graph
Graphical
Gut or Gut feeling
GIT
Gitlab
Github
GIF
GPS
GUI
GSM
Game
Gate as in logic gate
Generation
General or generality
Generic
Generate/Generative
Gigabyte
GPU
Generation
Greycode
Guidewire
Guidance
grep, a powerful tool to extract text from a file using a regular expression.
It can be used on different operating systems like Linux, Apple, and Windows.
Power users like to pipe it on UNIX variants.
G is usually for “GAAAAAAAH WHY CAN’T I REPLICATE THIS ISSUE?!”
Grey box testing
GHDB (Google hacking database)
Granular access controls
GPU-enhanced Geofencing
G is for Goldilocks.
Too Big, Too Small, Just Right.
How might we test when things are too big, too small and just right? What information does it reveal?
Who would’ve thought a fairy tale could help trigger test ideas? 
G is for Go! Live
G is for gatekeeper
G is for gentle and gracious - how we hope people are when reporting bugs, finding their code has bugs, and debating how and when to fix them.
G is for getting / grokking users - a way in which a tester can be valuable is by really understanding how users use the system (rather than how product owners or developers think they should use the system).
G is for going off piste - as well as testing the system should be used (according to the user story etc.), what happens if someone does something unexpected?