In Tehilim 29:1, it mentions the bene elim. Who are they? Please cite sources. It seems to have been quoted in the piyut Shinamim by Solomon Ibn Gabirol (page 134 of the Spanish Portuguese Kippur service). My guess over there is that they are angels. But it might also be a call for the righteous people to praise God.
bene elim - you and me!– Rabbi KaiiFeb 6 at 10:34
There are several opinions:
Rashi - They are to be understood as "שרים" - officers
Ibn Ezra - they are "כוכבים" - stars
The Targum draws the same conclusion as you that they are "כַתֵּי מַלְאֲכַיָא" - groups of angels. This view is additonally upheld by Metzudas Dovid
Metzudas Zion looks at this language of "אלים" which connotes power and strength, and draws parallels with the nation of Moav (as per Shemos 15:15) where it says "אלי מואב" - lit. "The powerful ones of Moav".
The Torah Temimah says the expression of "אלים" is a reference to the אבות our Patriarchs and proves this with a quote from the Gemara in Megillah 17b which brings this verse:
ת"ר מנין שאומרים אבות שנאמר (תהלים כט, א) הבו לה' בני אלים ומנין שאומרים גבורות שנאמר (תהלים כט, א) הבו לה' כבוד ועוז ומנין שאומרים קדושות שנאמר (תהלים כט, ב) הבו לה' כבוד שמו השתחוו לה' בהדרת קדש
The Sages taught in a baraita: From where is it derived that one says the blessing of the Patriarchs, the first blessing of the Amida? As it is stated: “Ascribe to the Lord, mighty ones” (Psalms 29:1), which means that one should mention before the Lord the mighty ones of the world, i.e., the Patriarchs. And from where is it derived that one then says the blessing of mighty deeds? As it is stated in the continuation of that verse: “Ascribe to the Lord glory and strength” (Psalms 29:1). And from where is it derived that one then says the blessing of holiness? As it is stated in the next verse: “Give to the Lord the glory due to His name; worship the Lord in the beauty of holiness” (Psalms 29:2). (Sefaria translation)
Similarly to the Torah Temimah's view brought by @Dov, Rabbi Yesha'ayhu of Trani wrote that "Bnei elim" refers to the descendants of Avraham, Yitzchak and Yaakov who were of "elei ha'aretz". This is per the midrash in Tanchuma Tzav 1:
"[“Among the children of the powerful ones” is referring to] the children of Abraham [which] are Isaac and Jacob. [These are the ones] who are the rams of the world."