בֵּ֣ית הַ֭לֵּוִי בָּרֲכ֣וּ אֶת־יְהוָ֑ה יִֽרְאֵ֥י יְ֝הוָ֗ה בָּרֲכ֥וּ אֶת־יְהוָֽה׃
O house of Levi, bless ye the LORD; Ye that fear the LORD, bless ye the LORD.
Rashi on Psalms
those who fear the Lord These are the proselytes (I found this).
Metzudat David on Psalms
"Those who fear G-d" - the righteous among the gentiles.