This is only the start - I've already found some more hacks that will be reviewed soon.
A note: I did not play any of these games, I only read them.
Minimal GLOG is an attempt to package an almost entirely orthodox (read: like Rat on a Stick) GLOG ruleset in the smallest possible space.
- Standard derived stats (Attack, Defend [called AC], Movement) except Stealth.
- HP and Stat Bonuses use equations (CON - 4 and [Stat / 3] - 3 respectively).
- May or may not be classless - the first page has rules for classless levelling, but someone else has added a section on more standard GLOG levelling.
- Extra magic uses - Papercasting (codified use of scrolls) and Consultation (cast spell to ask it questions related to its purpose).
- Appendix on miscellaneous rules - overland travel, hirelings, professions.
But the question is - does a generic fantasy GLOG hack actually need any of these things? After all, the only thing that really matters to most readers is a good mechanic or two they can steal, and Minimal GLOG has that not just in its Papercasting and Consultation, but also in its simple HP and stat generation.
Jar of Dirt
In contrast to Minimal GLOG, Jar of Dirt is a large, setting-focused GLOG hack built to provide a low-magic piratical game.
- Setting intro, largely stolen from Skerples' own pirate GLOG.
- Uses d20 + half Stat ≥ 20 as a base system, instead of the more common roll-under.
- Less hardcore stat generation - 4d4 base with switching and 2 free points to add.
- 3-axis alignment (Superstitious/Skeptical, Romantic/Cynic, Traditionalist/Radical).
- Fast healing - 1 hour of lunch returns 1d6+level, a night of sleep returns all HP.
- 5e-style Exhaustion as an extra track for environmental hazards.
- Hirelings are heavily abstracted and treated as a single mass in combat.
- As well as Classes, characters have nationalities, professions, and skills, quickly and easily adding more character differentiation.
- Levelling is based on Into the Odd - based on number of expeditions survived (as well as some extra requirements for high levels) and rewarding you with in-universe benefits.
- Slightly more complex 5e-style combat.
- Simple death and dismemberment seemingly a cross between the Many Rats table and Cavegirl's method.
- Most classes are from Skerples' pirate GLOG, although some are from other sources.
- Ship rules (sailing exploration, ship combat, etc.) from Skerples' pirate GLOG.
- Some setting-specific tables (I search the body, life goals, sailor's stories)
Nidus is another short hack, meant to be a Call of Cthulhu-style supernatural horror game.
- 5 stats - Brawn, Agility, Willpower, Vigor, and Luck.
- Occupations give you a set of possible Connections (an Artist having a connection to a publishing house they've worked with) and letting you roll 5d4 for one of your stats.
- Skills, ranked from 1-4. The value is added to your stat for relevant rolls.
- Standard roll-under checks.
- Combat is similar to Many Rats, with a couple changes - separate Melee and Ranged derived stats, and Defense being replaced with damage reduction.
- Levelless system - every 3 critical failures or critical successes with a stat, you can attempt to increase it by rolling over it on 4d4. Skills are increased in the same way.
- Into the Odd-style health - when your HP runs out, you get a Wound and start taking damage to your Vigor. The Death and Dismemberment table is a very simple d6 roll with death occurring if the same entry is rolled twice.
- Simple meter-style tracking for Sanity - as the derived stat decreases, you gain penalties off a pair of tables.
- Spellcasting is largely unexplained, but doesn't seem to work on a standard GLOG system - instead, each spell cast gives you a point of Corruption, causing you to take more HP damage.
Either way, it has a few things possibly worth taking for a more traditional hack - the Death and Dismemberment system is wonderfully simple, and Nidus's skill system is one of the best ways I've seen skills implemented in a roll-under system.