Thoughtseize Bug B
Sorcery
Target player reveals their hand. You choose a nonland card revealed this way. They discard it. Then they may search their library for a card with the same name as the discarded card. If they do, they shuffle their library then put that card on top.
That is a pretty stupid solution. Not all tournaments have decklists and even the ones that do don't necessarily give access to everyone's decklists to everyone else.
And this is an instant win combo with Aven Mindcensor, or Shadow of Doubt, or anything that affects whether a library can be searched. But it is only an instant win if you call the judge right away which means that is what is going to happen because this card incentivizes lying by the player being targeted so a judge call is the only way to ensure they have another card in their library with the same name. And if the player didn't have another card with that name in their library, you just wasted everyone's time.
The complicated you win the game scenario appears to be tacked on to prevent cheating. However there is a much better solution if that is the goal. And it allows you to more faithfully reproduce the "thoughtseize bug".
Target player reveals their hand. You choose a nonland card revealed this way. They discard it. Then they may search their library for a card with the same name as the discarded card. If they do, they shuffle their library then put that card on top.
The other issue with this is that, if the person has three or four copies of the named card, this specifies they only remove one from their deck. There are then 1-2 other copies of the card (not that you have a way to prove that since their deck isn't public information during the game) and should lose.
Your "lose the game" functionality just doesn't work like you want it to, and you should look at cards like Lobotomy as an example to set your card up better. Additionally, you need to either target opponents specifically or exile the cards, because this is a super efficient way to get three copies of something into your own graveyard by targeting yourself.
I suggest this:
Thoughtseize Bug B
Sorcery
Target player reveals their hand, then you choose a non-land card from it. Search that player's library for all cards with the same name as the chosen card and them into their graveyard. Then that player shuffles. The next time that player would draw a card, they skip that draw instead.
I do like the "skip draw" as psuedo-discard, though the ability is very niche and this is only really a sideboard against certain decks with very specific win cons.
Sorcery
Target player reveals their hand. You choose a nonland card revealed this way. They discard it. Then they may search their library for a card with the same name as the discarded card. If they do, they shuffle their library then put that card on top.
And this is an instant win combo with Aven Mindcensor, or Shadow of Doubt, or anything that affects whether a library can be searched. But it is only an instant win if you call the judge right away which means that is what is going to happen because this card incentivizes lying by the player being targeted so a judge call is the only way to ensure they have another card in their library with the same name. And if the player didn't have another card with that name in their library, you just wasted everyone's time.
Target player reveals their hand. You choose a nonland card revealed this way. They discard it. Then they may search their library for a card with the same name as the discarded card. If they do, they shuffle their library then put that card on top.
Your "lose the game" functionality just doesn't work like you want it to, and you should look at cards like Lobotomy as an example to set your card up better. Additionally, you need to either target opponents specifically or exile the cards, because this is a super efficient way to get three copies of something into your own graveyard by targeting yourself.
I suggest this:
Thoughtseize Bug B
Sorcery
Target player reveals their hand, then you choose a non-land card from it. Search that player's library for all cards with the same name as the chosen card and them into their graveyard. Then that player shuffles. The next time that player would draw a card, they skip that draw instead.
I do like the "skip draw" as psuedo-discard, though the ability is very niche and this is only really a sideboard against certain decks with very specific win cons.
Per Contemporary Reference