Toddler will be able to keep herself company some of the time now, and could have fun sorting her toys into groupings, such as by shape or by colour. In this way she's demonstrating that she knows how some things vary and some things are similar. She'll be putting a lot of her thought and brainpower into her own little games, and won't be happy if anyone interrupts her or wants to try and play with her, and so she'll be very grabby and grumpy with them.
Be careful not to spoil your child at this age - firm boundaries and rules are crucial. If limits are set then they must be enforced consistently. There's no point in having rules if you let baby break them one day and not the next day. Just like in the real world, actions should have consequences, and baby will ultimately benefit and be happier if they know exactly where they stand.