Rashba

General

1. The Rashba was a student of the Ramban and Rabbeinu Yonah, and he was the primary opponent of the Ra'ah.m His students include Rabbeinu Bechaye ben Asher and the Ritva
2. The Rashba had editions of Tosafot other than the one printed on the page of our Gemaras.
3. The Baalei HaTosafot and Rashba share a similar approach, therefore, if the Rashba copies Tosafot, it's a sign of agreement.
4. Maharashdam relates often how his rebbe, Maharitatz would weigh the Rashba's position on a matter equal to the majority of Poskim. Similar statements are made by Rav Yosef Karo and the Radbaz.
5. The Kenesset HaGedolah recommends following the Tashbetz over the Rashba, as he came later. On the other hand, the Beit David advises following the Tashbetz over the Terumat HaDeshen, even though the latter was later and deserves much honor, because the Tashbetz was simply much greater.

Torat HaBayit and Mishmeret HaBayit

1. The Torat HaBayit comes in two parts, "Aroch" and "Katzar." The Aroch explains the topics from the Gemara, and the Katzar is just a list of the conclusions. The Rashba expressed dissatisfaction with those who only wanted to spread the Katzar and not the Aroch, but, unfortunately, even when it was eventually printed, the printers, not just the copyists, did just that. Indeed, there are more manuscripts of the Katzar than the Aroch, indicating a greater reach by the Katzar than the Aroch. Therefore, Rishonim like the Tur never saw the Bayit HaAroch.
2. The Ra'ah wrote a critique of Torat HaBayit known as Bedek HaBayit.
3. The Mishmeret HaBayit was written by the Rashba to defend himself against the Ra'ah, but it wasn't in print at the times of the Beit Yosef, Rama, and Maharshal for them to see it.

Avodat HaKodesh

1. In Avodat HaKodesh, the Rashba's Sefer on Shabbat, Yom Tov, and Eruvin, he writes "יראה לי" when referring to Halachot from the Yerushalmi, Tosefta, and anything else not mentioned in Talmud Bavli.
2. Like the Torat HaBayit, the Avodat HaKodesh also has an "Aroch" and "Katzar," but the "Aroch" is no longer extant. Thus, our Avodat HaKodesh is only the "Katzar." However, some modern editions include a collection of quotations from the "Aroch" from Rishonim who did have it.
3. Some Rishonim refer to Avodat HaKodesh as "Torat HaBayit" informally.

Shu"T HaRashba

1. The Rashba wrote thousands of Teshuvot.
2. The extant Shu"t HaRasha are a condensed version of the original.
3. Due to the fact that the Shu"t HaRashba printed in the times of the Beit Yosef was mistakenly attributed to the Ramban, the Beit Yosef refers to it as Shu"t HaRamban, even though he knew it was really the Rashba's. This way, one who seeks to look up the source will know which Sefer to open.
4. Some volumes of the Rashba are known as "Toldot Adam" according to some Rishonim.

Misc.

1. The Rashba also wrote a commentary on the Aggadot of Shas.
2. He also had a hand in Kabbalah.
3. A large chunk of Chiddushei HaRashba on Avodah Zarah, from 21b to 51a, is really the Tosafot HaRosh.
4. There's a discussion regarding the authenticity of the Chiddushei HaRashba on Menachot. See the introduction in the back of the Oz VeHadar volume on Menachot, where it's printed.
5. In order to resolve contradictions, the Sdei Chemed delineates the order of authority and reverse chronology as follows:
   1. Shu"t HaRashba
   2. Torat HaBayit / Avodat HaKodesh / Piskei Challah / Shaar HaMayim
   3. Chiddushei HaRashba

Further Reading

1. Introduction to Torat HaBayit, Mosad HaRav Kook edition
2. Later Rishonim VI: Rashba, by Rabbi Aryeh Leibowitz