Assalamu alaikum. Forgive me brothers and sisters if I am repeating any of the books that you might have mentioned before but I confess that I did not read all the posts in this thread. However even if they have been already recommended it is worth repeating them again
(Alla the books I will mention are also translated in English al-hamdulilah)
First of all the Qur'an
Then "The three fundamental principles" by sheikh ul-Islam Muhamed ibn Abdul-Wahab and it's explanation by sheikh Abdur-Rahman ibn Muhammed ibn Qasim and Muhamed ibn Salih el-Uthaymeen. Then:
Kitab et-Tawhid again from Abdul-Wahab and it's explanation Fat'h el Majeed with the footnotes and explanations of sheikh Ibn Bazz. There is also the version without the comments of Ibn Bazz. Then:
Kashf esh-shubuhat fi tawhid from Abdul-Wahab and you will find it in english translated by Ammar Yasir Qadhi as A critical study of shirk. Then:
Masail ul jahiliyah from Abdul-Wahab and explained by sheikh Salih el-Fawzan as "An explanation of the aspects of the days of ignorance". then:
El-Aqidatil- wasatiyah of sheikh ul Islam Ibn Taymiyah and it's explanation from sheikh Muhammed Khalil Harras and also from sheikh Muhamed ibn Salih el-Uthaymeen. Then:
El-Aqidatil hamawiyah again from Ibn Taymiyah and it's explanation from sheikh Uthaymeen. Then
El-Aqidatil-tadmuriyah from Ibn Taymiyah and it's explanation (I do not know if available in english) by sheikh Uthaymeen. then:
El-Aqidatil-tahawiyah by Tahawi and it's explanation from Ibn Ebi'l-Izz el-hanafi and also from sheikh Ibn Bazz and Salih el-Fawzan. then:
The sufficancy in creed of Imam ibn Qudamah el-Maqdisi and it's explanation from sheikh Ibn Uthaymeen. Then:
Foundations of the sunnah of Imam Ahmed. then any such books like that Imam Barbahari and others. then:
Exemplary foundations concerning the Beautyful Names and Attributes of Allah of sheikh Ibn Uthaymeen. then:
The names and attributes of Allah of sheikh Sulayman el-Ashqar. then
Kitab ul-iman of Ibn Taymiyah. then any books from Ibn Taymiyah and Ibn Kajjim. Also books in hadith begining with Sahih el-Bukhari and Muslim and so on.
These are but a few books mentioned and are all in english al-hamdulilah and whoever has read them will agree with me that until you have read and digested them, you really do not know anything about our deen except general stuff. These books will help a lot.
By Allah, if anyone had to travel for half of his/her life to obtain them and spent the other half studying them and understanding them while acting upon them, he/she would have fulfilled his/her obligation of seeking knowledge.
Wa salamu alaikum wa rahimatullahi wa barakatuhu.