It's interesting to think about how the Old Testament regards the various deities of tribes around the Israelites.
The Canaanites worshipped El, and the Scriptures make no distinction at all between the Lord (YHWH) and El. It's unclear how much to make of this, since 'El' eventually became the generic word for any high God in the area, but we can say straightforwardly that there is no sign that the Israelites ever had any problem with the worship of El, considered on its own.
The Edomites worshipped Qos (or Qaus or Koze), and there is also no sign of any animosity toward Qos in Scripture, despite the fact that the Israelites were regularly interacting with Edomites; the name only even comes up twice for sure (and then only in the name Barqos: Ezra 2:53, Nehemiah 7:55), and possibly it might underlie the very difficult-to-interpret Hebrew of Proverbs 30:31 (which we usually translate as 'king with his host', but might originally have read 'Qos with the king'). There are a few old inscriptions (from Kuntillet Ajred) that possibly refer to Qos as "YHWH of Teman", so some people have suggested that they were just seen as the same. Others have suggested that Qos might not have been a name but a title. There's a lot we don't know here, but again it's interesting that worship of Qos wasn't seen as an issue by any of the Jewish prophets. (The first sign of any trouble over between Jews and Edomite worshippers of Qos is in the Hasmonean period, when the Hasmoneans cracked down on Edomite worship, but that seems to have been a cultic crack-down arising for political reasons.)
Three local tribal deities are firmly and repeatedly rejected in Scripture: Ashtoreth (Attartu/Astarte), Chemosh (Kamosh), and Milcom (Milkam). They are explicitly stated to be foreign and their worship is said to be offensive to the Lord. Milkam was worshipped by the Ammonites, and we know almost nothing about him; he is referred to in Scripture as 'desolation' and 'abomination'. We have a few seals that associate Milkam with bulls and maybe the stars. He might be the same as Moloch, although we don't know for sure.
We know a bit more about Kamosh. He was worshipped by the Moabites; the Moabites were Canaanites, but there seems reason to think that they had a very distinctive worship. In Moabite inscriptions, Kamosh is associated with the planet Venus, the morning star, and the Semitic deity Attar. Although it is limited, there is definitely evidence that his worship involved human sacrifice, at least under specific conditions (like war), and that the Moabite worship may have actively involved appealing to him for curses. In later days, the Greeks associated him with Ares, and he may well have had similar brutal characteristics, since he does seem to have been a war-god. Scripture also refers to him as 'abomination'.
Ashtoreth, of course, is the foreign 'abomination' we know most about. She was a goddess, and she is always the consort of another god. So this is obviously one major strike against her: she is the guarantor of polytheism. If you worship her, you definitely worship multiple gods. She may be very, very old, since the Phoenicians almost certainly inherited her from the Akkadians and perhaps also the Eblaites, who formed one of the first organized kingdoms in the area. The Greeks associated her with Aphrodite, and it used to be thought that she was a fertility goddess, but actually this seems not to have originally been the case, and evidence of association with the explicitly erotic (e.g., temple prostitution) seems scattered and occasional, and perhaps mostly linked to Byblos and to Carthage. She's definitely associated with ships, lions, horses, and hunting. She may have been a war goddess, and in fact this might be one link between the three rejected deities -- they may be war gods whose worship involved abominable activities of various kinds in the name of war. Ashtoreth is often associated in Scripture with war, directly or indirectly, as when the Phoenicians put their war trophies in the temple of Ashtoreth. She is also regularly associated with Baalim.
Baal is not a single deity. The word is Canaanite for 'Lord', and different cities seem to have had each a Baal of that city. The earliest parts of Scripture don't seem all that hostile to Baal; it seems to be treated as just a divine title, and the Israelites may themselves have sometimes used it of their own God, if theophoric names and divine epithets are to be taken as evidence (e.g., Psalm 68:4 calls God 'cloud-rider', which was also an epithet of Hadad, the most influential local Baal). As time goes on, however, 'Baal' as a divine title becomes treated with greater and greater hostility in the Scriptural narrative. Since there are many Baalim and Scripture does not distinguish them, we don't always know which is meant, but there is strong evidence that the rejection of Baal is associated with two Baalim in particular: Hadad and Melqart, who are sometimes identified with each other. In any case, the Baal that was introduced into Israel by King Ahab and Queen Jezebel, and with whose worshippers the prophet Elijah kept struggling was almost certainly Hadad or Melqart. Melqart is associated with the Phoenician cities of Tyre and Carthage (although the chief Baal of Carthage was Hammon rather than Melqart). The Greeks associated him with Heracles. Beyond this, we don't know much about Melqart. Hadad, also called Rammanu/Rimmon ('the Thunderer'), was a storm god, and a very ancient one worshipped by the Akkadians and Eblaites; he is also the Baal who causes problem for El in the Ugaritic Baal Cycle.
Thus we get a full spectrum, from the accepted or at least neutral (El, Qos), to the heavily mixed (Baal), to the vehemently repudiated (Ashtoreth, Chemosh, Milcom). The two key sources of variation seem to be (1) relation to polytheism and (2) kind of worship. El, Qos, and some versions of Baal are, or seem to be, supreme deities, so it's easier to adapt their titles and names to monotheism; Ashtoreth and some versions of Baal are inherently polytheistic, and this is probably also true of Milcom and perhaps also Chemosh. Ashtoreth, Chemosh, and Milcom are associated with 'abomination' in worship, however that is understood, and the same may well be true of Hadad, at least in the version introduced into Israel. Thus worship of them made you directly complicit with evils.
Of course, all of this is really quite patchy. We can infer a fair amount about Baal Hadad and Ashtoreth, and to a lesser extent about El, because their worship was ancient and widespread, with lots of fragments of information about them across a long spread of time, but the evidence we get about even them is often limited and confused, and at times outright confusing. About the rest, we know considerably less, and even our best guesses are often not much more than guesses. Much of what we think we know for any of them could very well be upended with one good archeological find.