Non-command features...

GC Messager
Automatically prints messages regarding the java garbage collector immediately after any time the GC runs (server-side)

Lag Detector (dedicated server only)
Automatically detects lag spikes and prints messages regarding them

Omniscience Profiler...

The vanilla debug command is replaced with a new debug command, which triggers the Omniscience profiler instead of the vanilla one
/debug start - similar to the vanilla command (but using the Omniscience profiler instead of the vanilla one)
/debug stop - similar to the vanilla command (but using the Omniscience profiler instead of the vanilla one)
/debug average - displays the most recent profiling results in "average" format (average per tick)
/debug total - displays the most recent profiling results in "total" format (total over full profiling period)
/debug peak - displays the most recent profiling results in "peak" format (highest usage during profiling period)

Server-side commands...

/omni ai
Lists all AI tasks for the nearest entity (first section is target tasks, second is non-target tasks)

/omni entities
Shows some basic entity data for all loaded worlds (total entity count, player count, and count of entity with highest number in that world)

/omni memory
Shows some basic server-side memory usage statistics

/omni nbt hand
/omni nbt nearestentity
/omni nbt self
Shows the full server-side NBT of the item in hand, the nearest entity, or yourself

/omni pathing
Toggles the pathing visualizer for the nearest entity (shows real-time, 3D pathing in-world)

/omni threads
Shows detailed thread-specific resource usage
/omni threads <thread id>
Shows more detailed information for a specific thread (use "/omni threads" to see thread IDs and names in a list)

Client-side commands...

/omnic screens
Shows a log of recent GUI activity
/omnic screens live
Toggles "live mode" for GUI activity logging (will show GUI activity messages instantly when enabled)

/omnic nbt hand
/omnic nbt nearestentity
/omnic nbt self
Shows the full client-side NBT of the item in hand, the nearest entity, or yourself

Yes, you can use it in your modpack if you want (MIT license).

A list of my curseforge mods can be found here

Omniscience Debugger