This is a shortened version of my ultimate list of free Exodus commentaries, created for quicker reference. Commentaries covering the entire book are in boldface.
I especially enjoy Parker’s expository sermons on Exodus.
Babington | Bacon | Barnes | Bennett [“New Century Bible”] | Bush vol 1 (1–20) / Bush vol 2 (21–40) | Cook [“Speaker’s”] | Chadwick [“Expositor’s Bible”]| Driver | Edersheim | Exell [“Preacher’s Complete Homiletical Commentary”] | Hughes (1–23) | Kennedy | Latch | Lightfoot | Mackintosh | McNeile | Murphy | Nevin | “Ramban” (Rabbi Moses ben Nahman) |Rawlinson [“Ellicott’s”] | Terry & Newhall [“Whedon’s”] / alt. ver. | Willet
Ainsworth | Blunt | “Chizkuni” (Rabbi Hezekiah ben Manoah) | A. Jackson |Kalisch | Kenrick | Kidder | Morison | “Ramban” (Rabbi Moses ben Nahman) | “Sforno” (Ovadiah ben Ya’akov Seforno) | A. Wright
Whole Bible Commentaries & Study Bibles
Barnes | Benson | Bullinger | Calvin | Constable | Dodd | Gaebelein | Gill | M. Henry / alt. ver. / abridged ver. | Hewlett | Jamieson | Kitto | Kretzmann | Lange | Meyer | Meyer | Patrick | Poole | T. Scott | Sutcliffe | Trapp | T. Williams
Sermons & Lectures
MacLaren [“Expositions of Holy Scripture”] | J. Parker [“People’s Bible” vol. 2] | Thornton | Tuttle
Two resources in German: Baentsch | Holzinger
There are many more works, especially in Latin, that are available online. If you know of a work I’ve left out that’s freely available online, written in English, and in the public domain, please leave a suggestion in the comments.