Do we receive any tax credits or rebates for replacing a gas cooktop with an induction cooktop?

No, those appliances are not eligible for a tax credit on a federal tax return.

I recall the inflation reduction act had a section covering replacing a gas range with an induction range with the following credit:

• Up to 80 percent of the median HHI in your area, you get up to 100 percent of the cost of the new appliance (or up to $840, whichever is less).
• More than 80 percent but less than 150 percent of the HHI in your area, you get 50 percent of the cost of the new appliance.

It said to use IRS Form 5695, but there doesn't seem to be anywhere to apply for this rebate. Did this credit disappear? How can I get it?

That currently does not qualify for a credit on form 5695.  But your state may have a credit program for replacing a gas range with an induction range.

@inductioncredit