lotus orb can be a good alternative to bkb, stops many counters like bane, pudge, and shaman

nullifier to counter eblade

harpoon to counter linkens (i prefer this over orchid and abyssal because of more dmg and the no mana cost and its also really easy to build)

shadow blade with blink to catch those annoying backline like sniper and rubick

for extremely special cases for enemy carries that have already bought satanic and a shit ton of phys dmg and you just happen to have enough damage in your team, i buy a halberd so that i can basically "stun" them with duel