There are are a couple of links below for suggestions, in addition to Richard's comment, which is very valid.
In addition to Richard's comments
1) think about 'when you want to start' predictive matching - eg on the 2nd or 3rd character being typed - this speeds up the search a bit
2) to speed up the process for users if they have individual preferences, save the words they used and present them next time
C# winforms combobox dynamic autocomplete - Stack Overflow[
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IntelliSense TextBox in C#[
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