Fields - How many and how to associate an array...?

Fields - How many and how to associate an array...?

We track the number of specialities from a medical oganizaitons. Inititally, I wanted to use a drop down but I realized there are limits on number of entries. Now, I create custom text fields.  For example, Genetics _________.  A reponse might be the number we are tracking in text format such as a number like 5.. Once the number is received I want to apply a code to be associated with the entry. Curious on how others might approach this problem. So, there would need to be a table lookup that would return a value. I know I can use the sheet function but it is only near real time and not very effective.

Any thoughts?