Ketubot 66A

דמעשה ידיה היא, אמר רבי עקיבא לעצמה ⁠— מציאתה לא כל שכן?!

which is categorized as part of her earnings and to which the husband has rights, R' Akiva says the surplus belongs to her, then with regard to lost objects that she found, which are unrelated to her handiwork, do they not all the more so belong to her?

דתנן: ״קונם שאני עושה לפיך״⁠ — אינו צריך להפר. רבי עקיבא אומר: יפר, שמא תעדיף עליו יותר מן הראוי לו! אלא איפוך: מציאת האשה לבעלה. רבי עקיבא אומר: לעצמה.

That is R' Akiva’s opinion with regard to surplus, as we learned in a Mishnah (Nedarim 85a): With regard to a woman who said to her husband: Anything that I produce will be konam, i.e., forbidden like an offering, to your mouth, he need not nullify the vow. The vow never took effect at all because a woman cannot prohibit her husband from items produced by actions that she is obligated to perform for him. R' Akiva says: He should nullify the vow, lest she produce surplus that is more than the amount that is fitting for him, and the vow will take effect on the surplus, which she is not obligated to provide him. According to R' Akiva, any surplus belongs to her. The Talmud answers: Rather, reverse the opinions: Lost objects found by a wife belong to her husband; R' Akiva says: They belong to her.

והא כי אתא רבין, אמר רבי יוחנן: בהעדפה שלא על ידי הדחק ⁠— כולי עלמא לא פליגי דבעל הוי. כי פליגי בהעדפה שעל ידי הדחק: תנא קמא סבר לבעלה, ורבי עקיבא סבר לעצמה. אמר רב פפא: מציאתה כהעדפה שעל ידי הדחק דמי. פלוגתא דרבי עקיבא ורבנן.

The Talmud asks: But when Ravin came from Eretz Yisrael, didn’t he say that R' Yoḥanan said: With regard to surplus that is not produced through extraordinary effort, everyone agrees that it is the husband’s. Where they disagree is in a case of surplus that is produced through extraordinary effort. The first tanna holds that the surplus belongs to her husband, and R' Akiva holds that the surplus belongs to her. Apparently, there is no need to reverse the opinions, as R' Akiva acknowledges that there are instances in which surplus belongs to the husband (Rid). The Talmud responds: Rav Pappa said: A lost object found by a wife is comparable to surplus that is produced through extraordinary effort, as this is not a regular occurrence. Therefore, lost objects are subject to the dispute between R' Akiva and the Rabbis.