Use Word Sifter when the specialized helper tabs do not quite fit the lookup. Start with the broadest letter constraint you know, then add only the filters you need.

Build the letter pool

Put letters that may be used in Letters Available. Add letters that every match must contain to Letters Required, and letters that must never appear to Letters Excluded. In the available-letter field, . acts as a wildcard.

Use Starts With, Contains, Ends With, and the length fields to describe the shape of the words you want. Dictionary filters can include or exclude words by source.

Choose how letters are counted

Check Tile Rules? when each available letter may be consumed only once. In that mode, . creates a blank tile in Letters Available. Check Require All Letters? when every available letter must appear in each result.

Keep Pattern Letters Count checked when letters in Starts With, Contains, and Ends With belong to the available pool. Clear it when those letters come from somewhere else, such as letters already fixed on a board.

Fit a board pattern

Use Pattern to look for words around fixed letters in a row or column. Letters are fixed positions. Use . for open positions.

A pattern replaces Starts With, Contains, Ends With, and the length filters for that search.

Example board showing how a row pattern and a column pattern map to board squares and dots.
The highlighted row and column become the board pattern. Letters stay fixed; dots mark open squares to fill.
Example

With Letters Available set to WANET and Pattern set to .ALL.BY....THE., matches can include WALL, BYTE, and THEN.

Arrange the results

After a search, use Group By, Sort By, and Score System inside Results. These controls rearrange the current matches immediately without running the search again.