“Knickknack” O’Brian is the “new Aesop’s Pawnshop”.

For example, Knickknack gets Gain 2[$]. Draw 1 card. for sacrificing an empty Coalescence, while Aesop got Gain 3[$].. However:

• Knickknack “reimburses” you: if you buy for $1, you sell for $1, as well as the 1 card itself (like Geist).
• Aesop just “swindled” for you: if you buy for $1, you still sell for the full $3, having had a much higher floor than Knickknack.
• Its The first time each turn a run begins, … is a (slightly) more interactive Whenever your turn begins, …; and can even be (slightly) more frequent, since you can run immediately after installing the resource.
• Both enable if you trashed your … gates (of Simulchip or Boi-tatá).

Synergies:

• Multi-Cards: While Netrunner lacks “card tokens”, one Muse–Coalescence provides two, $2-cost sacrificeables (from a single click/card, over the next two turns).

• Cost-Redux: If more self-cost reductions get printed (like Carmen, which costs $3 to install but reads with a printed install cost of $5) in Shaper, then Knickknack can actually profit off the sacrifice (like Aesop did). As well as cost reductions in general (like DZMZ Optimizer and Simulchip).

• “Spendables”: With virus counters, like Pelangi (or Cordyceps?). And a few with power counters, IE. those without When this _ is empty, trash it., like Coalescence (or the new Devadatta Drone?); as well as the disposable breakers like Revolver (wasting only one “bullet”, to gain two credits and a card), or even Propeller.

• “Front-loaded’s” cards: With high-value When-Installed triggers (like 5inf The Class Act?).

• Compression: If you can compress installs (like the new Illumination, which also cheapens those installs), then Knickknack’s econ can “fully-reimburse” the sacrificed installations (credit, card, and click). Likewise within an Ari or Magdalene deck.

Thus Pawnshop, with its the higher floor and its non-interactivity, seems more powerful, but the design of O’Brian feels more exciting (IMO): you have to care about printed install costs, you get a “card flow” (like Geist), you have to make a run, and so on.

PS. My hope is a Shaper card with large self-cost-reductions, like:

• a gated [$5]; This resource costs 3[$] less to install if you've trashed one of your cards this turn., which works with the Pawnshop archetype (and Simulchip in any archetype).
• or even a scaling [$6]; This program costs 1[$] less to install for each power counter among active Runner cards., which is unbounded.

NB. While it can sac a 4[$] Principia that only cost you 2[$] to install (for Gain 4[$]. Draw 1 card.), you don't want to be sac'ing Fracters. Like how Aesop sac'd a just-used/off-matchup Paricia (for Gain 3[$].).