2. If you forgot to say Bismillah
بِسْمِ اللَّهِ فِي أَوَّلِهِ وَآخِرِهِ
Bismillaahi fee awwalihi wa aakhirih.
In the name of Allah at its beginning and its end.
Source: Abu Dawud 3767
3. After Eating
الْحَمْدُ لِلَّهِ الَّذِي أَطْعَمَنِي هَذَا وَرَزَقَنِيهِ مِنْ غَيْرِ حَوْلٍ مِنِّي وَلَا قُوَّةٍ
Alhamdu lillaahil-lathee at'amanee haathaa wa razaqaneehi min ghayri hawlin minnee wa laa quwwah.
All praise be to Allah who fed me this and provided it for me without any strength or effort on my part.
Source: Abu Dawud 4023, Tirmidhi 3458