Calcium is the mineral the body uses to build and maintain bone and teeth, and most people picture a glass of milk when they think about where to get it. That's the obvious source, but far from the only one, and some of the better options don't come from dairy at all.
Dairy is still the easiest place to start. A cup of milk or a serving of yogurt covers a large share of what most adults need in a day, and hard cheeses concentrate it further because so much water has been removed in the making. For anyone who doesn't eat dairy, calcium-set tofu is one of the closest substitutes. The calcium sulfate used to set the tofu adds a real amount of the mineral, not just a trace.
Leafy greens are the other major source, though not all of them equally. Kale and collard greens give up their calcium easily when digested; spinach, despite looking similar on a plate, contains oxalates that bind to calcium and make most of it unavailable to the body. If leafy greens are your main calcium source, kale and collards do more work than spinach does.
Sesame seeds are worth knowing about specifically because they're one of the few plant foods with a genuinely high calcium content per gram — tahini and halva both concentrate it further. Almonds carry a smaller but still useful amount, enough to matter if they're a regular snack rather than an occasional one.
Small fish eaten with the bones are another source most people overlook. Sardines and tinned salmon are the common examples, since the bones themselves are where most of the calcium sits.
Dates carry a modest amount of calcium alongside potassium and magnesium, not enough to be a primary source on their own, but a reasonable contributor if they're already a regular part of your diet. Where dates earn their place is as a stand-in for refined sugar in a snack that also includes something calcium-rich. A few dates stuffed with tahini pairs a source of the mineral with a sweetener that doesn't come from processed sugar.
None of this requires tracking every gram. Covering two or three of these sources across a normal week, dairy or tofu, a leafy green that isn't spinach, and a handful of sesame or almonds, gets most people where they need to be without any single food carrying the whole job. For dates as the sugar swap mentioned above, Iran Date Fruits Exporter has the current stock, or get in touch for wholesale quantities.