ON
Worth 2 points before any premium square, and the lowest-scoring of the 96 — tied with 35 others.
ON extends into 13 three-letter words, which is the 30th most extendable of 96 — tied with 5 others. That is the number worth memorising: a two-letter word is a place to put tiles, but a well-hooked one is a place to put them where the board stays open.
Every hook
- C→CON
- D→DON
- E→EON
- F→FON
- H→HON
- I→ION
- M→MON
- S→SON
- T→TON
- W→WON
- Y→YON
- E→ONE
- S→ONS
Not all of them are equally reachable, which a bare count of 13 hides. ON hooks on 11 distinct letters, and the ones you are likeliest to be holding are E (60% of opening racks), I (49% of opening racks) and T (36% of opening racks). The rarest is Y, at 14%.
How often you can actually play it
Out of an opening rack, 14.90% of the time you hold the letters for ON outright, the 17th likeliest of 96 — tied with 3 others. Counting a blank as whichever letter is missing lifts that to 21.81%, though spending one of the two blanks on a two-letter word is rarely the play. Exact hypergeometrics over the 100-tile bag, not a simulation.
It reverses
ON backwards is NO, which is also good. That is how most of this list is actually learned — 46 of the 96 come in reversible pairs, so knowing one gets you the other free.