Commonly build items that are actually bad on heroes.

Bloodstone is probably most valid on Timbersaw and Death Prophet imo. While the heroes you mentioned could get it, an Orchid Malevolence is usually better for a Storm Spirit (assuming you have a decent team and can rely on your teammates) and Leshrac as a support usually cannot get it and would probably not use Pulse Nova that much anyway.

Mid Leshrac could get it though, just don't like the idea of him going mid that much.

Too much hate on the Vanguard. It's actually a pretty decent item if you ask me: getting one on chasers like Doom and Ember Spirit makes tower dives very easy (just try it, you'll be amazed!) and the extra regen makes you able to lane or even jungle without needing to go back to base. The extra HP also soaks up the damage of an average mid-game nuke (~312 damage considering 25% magic resistance, more than both of Lina's nukes taken singularly) and the damage block helps even more. The extra regen is 6HP/s, which is a lot: the Ring of Health only gives 5 while the Force Staff only gives 3.
I don't think it's a must-have on any Hero, but it's too underrated; a Blade Mail is definitely worse since it won't help in any way against BKB holders. If it was disassemblable, I would definitely get it as a core on Spectre or Phantom Lancer instead of the Drums since the rework of Tranquil Boots made their laning phase really bad regen-wise.

About Soul Ring and Ring of Aquila, I don't think they're that bad or underrated - well, maybe the SR is but it helps very few Heroes like Dark Seer and Enigma. Aquila is very convenient for pushing (especially on Weaver and on Sniper if you max out Shrapnel first) and a really nice item to have for racecar builds if you start with a Wraith Band.

Mask of Madness: I absolutely hate it, I can't think of a nice Hero to pick it on except for a BKB'd Sven and a Faceless Void really focused on the early game (I still prefer Drums on him). If a Sniper gets fed with it, that's your fault for not picking a gap closer to fight him; same for Drow Ranger.

Bloodstone is also a good one, it is only good on some heroes becouse it doesnt benefit your team much except for the heal on death.

The heroes who could benefit from getting one are timbersaw, leshrac, storm spirit and death prophet. In this order.
Of these heroes only timbersaw should always try to get one. Leshrac like timbersaw needs to be close to dish out damage and eats mana so could get a lot of use out of one. Storm if you dont need an instant orchid to use against mobile heroes.
Death prophet doesnt need as much mana as the other heroes but the hp boost works great with her playstyle.

The problem is that some people get it on heroes that dont need that much mana, and could get much more use out of a scythe of vyse or even shivas guard.
Like rubick, lina, or worst of all, the hero that has fountain regen anyway, and must build as many active items anyway: tinker. AARRRGGGGGG!!!

Bloodstone also is useless unless you find ******s that feed. Linken's Sphere is much more better any case

Linken's Sphere is taken for different reasons as Bloodstone. The latter is taken for the mana regen and mana, and the former keeps those two as a plus to the main use of the item

(spell block to counter certain heroes, and synergy with the kit of the few heroes who use them. Weaver does take it partially for the mana regen, but for some other heroes that do take the item like Morphling, it's for a different reason)

The problem is that people get it on heroes like rubick who dont need it.

Vanguard on most of the heroes people build it on, battlefury on Jugg and bounty.
For the love of god, shadow blade on every hero when you're not initiating fights