This is one of the most comprehensive preterite charts. In addition to the regular verbs, it has (what I believe to be) model verbs for spelling/accent changes, stem-changes, the "special verbs" and the "magnificent verbs" (these terms coined by molinodeideas.es — check out their work).

The ZIP file contains three one-page PDFs:

• a fully filled out copy of the chart, complete with colored annotations

• a partially filled out copy, wherein students can write in just the endings or irregular portions

• a blank chart, which still has all of the categories on it, but the student will need to conjugate each verb in full

Added 2019-08-17