ED
Worth 3 points before any premium square, and the 44th lowest-scoring of 96 — tied with 7 others.
ED extends into 11 three-letter words, which is the 41st most extendable of 96 — tied with 3 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
- B→BED
- F→FED
- G→GED
- L→LED
- M→MED
- P→PED
- R→RED
- T→TED
- W→WED
- Z→ZED
- H→EDH
Not all of them are equally reachable, which a bare count of 11 hides. ED hooks on 11 distinct letters, and the ones you are likeliest to be holding are R (36% of opening racks), T (36% of opening racks) and L (26% of opening racks). The rarest is Z, at 7%.
How often you can actually play it
Out of an opening rack, 14.18% of the time you hold the letters for ED outright, the 21st likeliest of 96 — tied with 3 others. Counting a blank as whichever letter is missing lifts that to 21.86%, 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
ED backwards is DE, 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.